Experimental Evaluation of Triphosgene in Organic Synthesis: Understanding Its Selection Logic Through Reaction Tasks

1. What Triphosgene Is, and Where It Sits Within Phosgenation Reagent Systems

Triphosgene, abbreviated as BTC, is bis(trichloromethyl) carbonate. The name “triphosgene” comes from the fact that, in stoichiometric terms, it can provide three equivalents of phosgene, and it is therefore commonly regarded as a classical phosgene equivalent. A representative paper published in 1987 described it as a crystalline phosgene substitute, and that understanding remains valid today.

Triphosgene is commonly used in research and small-scale organic synthesis, mainly because it is a solid, which makes it relatively convenient to weigh, add portionwise, and incorporate into an experimental workflow. A 2020 review summarized its major applications from 2010 to 2019, covering organic halides, acid chlorides, isocyanates, heterocycles, as well as reactions in flow chemistry and solid-phase systems. Reviews and commonly used reference materials show that, among common phosgene-substitute systems, diphosgene and triphosgene are generally closer to traditional phosgene-type routes involving highly reactive intermediates, whereas CDI (N,N′-carbonyldiimidazole) and DSC (N,N′-disuccinimidyl carbonate) are more often used in milder arrangements based on activated esters, active carbonates, or acyl transfer. Accordingly, the place of triphosgene in experimental work is reflected not only in its operational convenience, but also in the fact that its coverage of reaction tasks is closer to that of phosgene.

Under pseudo-first-order kinetic comparison in CDCl₃ at 25 °C with methanol in excess, Pasquato et al. reported relative reactivities of approximately 170, 19, and 1 for phosgene, diphosgene, and triphosgene, respectively. This indicates that, in that methanolysis model, the defining feature of triphosgene is not maximal reactivity; its common advantages in research and small-scale work arise more from the convenience of weighing, charging, and organizing experiments that comes with its solid form. At the same time, excess triphosgene cannot be removed as readily by volatility as phosgene can, so residue handling and workup are often more troublesome. This point requires especially careful prior evaluation when the target intermediate is sensitive to water or alcohols. Therefore, deciding whether triphosgene is suitable for a given reaction requires simultaneous consideration of the task type, intermediate stability, workup requirements, and safety conditions.

2. Major Reaction Types of Triphosgene Summarized by Experimental Task

From the standpoint of experimental tasks, the common reaction types of triphosgene can be summarized as follows. This classification integrates review articles and representative primary literature, including the preparation of N-carboxyanhydrides (NCAs), the conversion of 1,2- and 1,3-diols into cyclic carbonates, the conversion of amines into isocyanates, and carboxylic acid activation.

Experimental task	Main role played by triphosgene	When to consider it first	Key point for prior evaluation
Activation of alcohols and phenols	Phosgenation or chloroformylation reagent	When a chloroformate must first be formed, followed by conversion into a carbonate or carbamate	Whether the highly reactive intermediate must be preserved, and whether workup can avoid destruction by water or alcohols
Cyclization of 1,2- or 1,3-diols	Carbonylative ring-closing reagent	When the goal is to directly construct a cyclic carbonate	Substrate configuration, steric hindrance, and base conditions can markedly affect the outcome
Carboxylic acid activation	Carboxylic acid preactivation reagent	When the key challenge is to deliver the carboxylic acid into a highly reactive acyl intermediate	Intermediates such as acid chlorides and anhydrides are sensitive to moisture and workup conditions
Carbonylative conversion of primary amines and related nitrogen-containing substrates	Phosgenation reagent for nitrogen-containing substrates	When isocyanates, carbamoyl chlorides, or further conversion to ureas are needed	Acid generation, overreaction, and handling of salt byproducts
Preparation of N-carboxyanhydride monomers from α-amino acids	Cyclocarbonylation reagent	When the goal is to obtain an NCA monomer	The intermediates are sensitive, and moisture, acid, and operating conditions in the system all require strict control
Dehydrative functional-group transformations	Dehydrative phosgene equivalent	When the precursor type matches the target product and activation and dehydration are ideally merged into one pathway	Substrate differences are large, and side-reaction pathways show clear substrate dependence

3. How to Judge Whether to Use Triphosgene: First Look at the Task Type, Then at Whether the Workup Is Compatible

Whether triphosgene should enter the shortlist of preferred routes usually depends first on whether the step is a typical phosgene-type task, and then on whether the target intermediate and workup conditions allow this route to be used. For tasks involving carbonyl introduction, chloroformylation, or dehydrative transformation, triphosgene and diphosgene are closer to phosgene-type reagents. For tasks centered on carboxylic acid activation and acyl transfer, CDI, that is, N,N′-carbonyldiimidazole, is often more direct. At the actual experimental stage, what truly determines whether triphosgene should rank among the preferred options is whether the intermediate is sensitive, whether the workup is feasible, and whether the reaction can proceed smoothly into the next step after completion.

Key point in the decision	Question that must first be clarified	Influence on whether triphosgene should be selected
Task type	Whether the current step belongs to a typical phosgene-type transformation	If it is a phosgene-type task, triphosgene can usually enter the shortlist of preferred routes
Nature of the intermediate	Whether highly reactive intermediates such as chloroformates, carbamoyl chlorides, isocyanates, acid chlorides, or NCAs, that is, N-carboxyanhydrides, will be generated	If the intermediate must be preserved, route selection should shift early toward the feasibility of workup and transfer
Quench and workup	Whether excess reagent can be treated with conventional water or alcohol quenching after the reaction	If the target intermediate is sensitive to nucleophilic quenching, the operational difficulty of the triphosgene route increases markedly
Residue control	Whether excess reagent and byproducts can be removed cleanly enough	If residues will affect the next step or product stability, the priority of triphosgene should be lowered
Integration with the next step	Whether the intermediate will be carried directly into the next step in situ or needs to be isolated and purified	In situ conversion makes it easier to exploit the advantages of triphosgene; if a sensitive intermediate must be isolated, the route becomes more demanding

4. The Control Points That Require the Earliest Priority Once Triphosgene Is Chosen

Once triphosgene is used, the main points of judgment center on the match between acid generation and base usage, and on whether highly reactive intermediates should be advanced in situ or isolated separately. For sensitive intermediates such as chloroformates, carbamoyl chlorides, isocyanates, acid chlorides, and NCAs, that is, N-carboxyanhydrides, excess reagent cannot simply be treated with water or alcohols, and transfer and workup after reaction completion often become even more critical.

Key control point	Question requiring focused evaluation	Influence on experimental outcome
Whether acid generation matches base usage	Whether the acid generated in the system will affect the substrate, product, or intermediate; whether adding base truly improves the reaction rather than increasing the burden of byproduct salt handling	Improper base use can increase side reactions and workup complexity, and adding more base is not necessarily better
Whether the intermediate is advanced in situ or isolated and purified	Whether the current step serves as an activation node for the next step, or whether the intermediate must be isolated separately	In situ progression usually makes it easier to realize the workflow advantages of triphosgene; when sensitive intermediates must be isolated, system cleanliness and workup become more demanding
Whether the quench and transfer mode is compatible with the target	Whether conventional treatment can be used after reaction completion, and whether the target structure tolerates water, alcohols, or other nucleophilic conditions	In systems involving sensitive intermediates, the mode of reaction termination itself may determine whether the route is viable

Among these factors, the match between acid generation and base usage particularly requires independent evaluation. A 2007 study on the preparation of isocyanates from amines showed that, under triphosgene conditions of this kind, the additional use of amine bases did not offer a clear advantage in most cases; conditions without an added strong base were instead more favorable for simplifying workup, while only substrates that were more acid-sensitive required assistance from a base. Therefore, in systems of this type for preparing isocyanates from amines, bases in triphosgene chemistry are better treated as condition variables that require separate evaluation, rather than as default components to be added routinely.

5. Key Points in the Safety Evaluation of Triphosgene Routes

Although triphosgene is a solid phosgene equivalent that is convenient for weighing and small-scale operations, it should not therefore be understood as “safe phosgene” or “a safer phosgene.” In experimental decision-making, priority should still be given to controlling inhalation exposure, avoiding contact with moisture or water, and planning the quench and workup after the reaction is complete.

The main points in experimental safety evaluation are concentrated in the following aspects:

Key point in safety evaluation	Question that must first be clarified	Influence on experimental organization
Control of inhalation and moisture exposure	Whether fume-hood operation is available, and whether exposure and moisture ingress can be controlled during weighing, transfer, and charging	Determines whether the route can be carried out under basic safety conditions
Mode of reaction termination	Whether the target intermediate tolerates conventional treatment with water or alcohols, and whether the quenching plan will destroy the target structure	Determines whether transfer and workup can be completed safely and cleanly after reaction completion
Scale-up conditions	Whether off-gas treatment, charge control, and the necessary engineering management are available	Determines whether small-scale feasibility provides a basis for further scale-up

Publicly available information shows that triphosgene is moisture-sensitive and can release toxic gases upon contact with water. For sensitive intermediates such as chloroformates, carbamoyl chlorides, isocyanates, acid chlorides, and NCAs, that is, N-carboxyanhydrides, excess reagent cannot simply be handled in the usual way with water or alcohols. The transfer mode and workup conditions after reaction completion often determine route viability at an earlier stage than expected.

6. Navigation Table for Experimental Selection of Triphosgene in Organic Synthesis (Choose Table 1-Table 4 by Research or Experimental Goal)

Research or experimental goal	Which table to consult first	Why this table should be consulted first	Which table to consult in combination	Guidance
To build an overall understanding of the triphosgene system first, and distinguish what the core reagent, control reagents, and preformed activated species are each best suited to address	Table 1	Table 1 brings together triphosgene itself, CDI, oxalyl chloride, thionyl chloride, DSC, NHS, and preformed chloroformate control reagents, making it suitable for first judging whether the current task belongs to phosgenation, carboxylic acid activation, or an active carbonate/activated ester route	Then see Table 2	Once the question of “which type of activation mode should be used to drive the reaction” is clarified first, it becomes easier to build a complete experimental judgment before moving on to bases, catalysts, and specific substrate screening
To compare the differences between triphosgene and routes based on CDI, oxalyl chloride, thionyl chloride, and related reagents, and decide which route should be tried first for carboxylic acid activation or chloroformate formation	Table 1	Table 1 directly provides the most important route comparators, making it convenient to compare different activation pathways in terms of intermediate type, workup mode, and substrate compatibility	Then see Tables 3 and 4	If the task falls on carboxylic acids, alcohols, amines, or dehydration substrates, Tables 3 and 4 can then be used to examine specific model substrates and representative products, making route comparison easier to translate into actual experiments
To establish the basic conditions for triphosgene reactions and compare the effects of bases such as pyridine, triethylamine, DIPEA, N-methylmorpholine, and 2,6-lutidine	Table 2	Table 2 focuses on acid scavenging bases, hindered bases, catalysts, and workup bases, and is suitable for setting up a basic condition framework for triphosgene reactions	Then see Table 1	It is more helpful for condition optimization to first use Table 2 to decide how bases and catalysts are organized, and then return to Table 1 to judge which activation reagent or control reagent should be paired with them
To carry out triphosgene reactions of alcohols, phenols, or diols and determine whether the route should proceed through chloroformate formation, carbonate formation, or cyclic carbonate formation	Table 3	Table 3 brings together hydroxy substrates such as benzyl alcohol, phenol, ethylene glycol, 1,3-propanediol, and glycerol, making it suitable for first judging from substrate type whether the task involves monohydroxy carbonylation or diol cyclization	Then see Tables 1 and 2	After reviewing Table 3, returning to Table 1 to choose between triphosgene and preformed chloroformate routes, and then using Table 2 to determine the base and catalyst, makes the experimental pathway clearer
To study the selectivity of polyhydroxy substrates in triphosgene systems and judge whether over-carbonylation or multistate-site reaction is likely to occur	Table 3	The glycerol, diol, and phenolic substrates in Table 3 are more suitable for evaluating the effects of hydroxyl number, site differences, and substrate structure on selectivity	Then see Table 2	In tasks of this kind, the issue is often not only whether reaction occurs, but whether the base, catalyst, and charging mode will amplify competition among multiple reactive sites
To drive carboxylic acids into more highly reactive intermediates and compare whether the triphosgene route or a classical acid chloride route is more suitable	Table 1	Table 1 places triphosgene, oxalyl chloride, thionyl chloride, DSC, and NHS together as key activation routes, making it suitable for first judging whether in situ phosgenation, acid chloride formation, or active ester formation should be prioritized	Then see Table 3	Once the route has been determined, actual screening can then be organized with model substrates such as acetic acid and benzoic acid in Table 3, making it easier to obtain meaningfully comparable data
To examine the conditions under which primary amines form isocyanates, ureas, or carbamates under the action of triphosgene	Table 3	Table 3 brings together representative primary amine substrates such as aniline, benzylamine, and cyclohexylamine, making it convenient to compare the reactivity differences of aromatic amines, aliphatic amines, and alicyclic amines in triphosgene systems	Then see Tables 4 and 2	First use Table 3 to define the substrate type, then use Table 4 for representative isocyanate or urea products, and Table 2 to optimize acid scavenging bases and catalysts, which is more suitable for a complete evaluation of amine-related tasks
To investigate chemistry centered on the isocyanate node and clarify the relationship between amine substrates and downstream construction of ureas or carbamates	Table 4	Table 4 provides representative intermediates/products such as benzyl isocyanate and diphenylurea, making it suitable for first clarifying the main convergence directions of amine transformations in triphosgene systems	Then see Table 3	Once the target product type is clear, returning to Table 3 to choose amine substrates makes it easier to arrange reaction design and endpoint analysis
To prepare amino-acid NCA monomers and build a basic understanding of the use of triphosgene in cyclocarbonylation of amino acids	Table 3	Glycine in Table 3 is the direct precursor entry point, making it suitable for understanding the NCA preparation task from the amino acid substrate itself	Then see Tables 4 and 2	Table 4 can then be used to confirm the target monomer type through the representative 2,5-oxazolidinedione entry, while Table 2 helps focus on acid scavenging and condition control, thereby reducing side reactions and decomposition
To investigate the use of triphosgene in dehydration to isocyanides or nitriles starting from formamides or oxime precursors	Table 4	Table 4 gathers dehydration-route precursors and representative products such as N-benzylformamide, benzaldoxime, benzyl isocyanide, and benzonitrile, making it suitable for first deciding whether the task converges on an isocyanide or a nitrile route	Then see Table 2	Such tasks are sensitive to base, water content, and workup. Once the product direction has been clarified, combining it with Table 2 to arrange conditions is more in line with actual experimental screening
To understand triphosgene reactions first from the perspective of “precursor-intermediate-end product”	Table 4	Table 4 is best suited for understanding several key endpoints of triphosgene chemistry from an outcome-oriented perspective: isocyanates, NCAs, ureas, nitriles, and isocyanides	Then see Tables 1 and 3	After first clarifying the target endpoint, one can then return to Table 1 to choose the activation system and Table 3 to choose substrates, making experimental design more focused
To build a triphosgene research framework for literature analysis or preliminary condition screening	Table 1	Table 1 is suitable for first establishing the route framework and sorting out the positions of triphosgene relative to several control reagents	Then see Tables 2, 3, and 4	Starting with route-level understanding and then adding condition components, substrate types, and representative products makes it possible to form a more systematic overall judgment of the experimental applications of triphosgene

Table 1 | Core Phosgenation Reagents, Activation Reagents, and Preformed Chloroformate Controls

Category	CAS No.	Aladdin Cat. No.	Name	Grade or Purity	Product Features and Applications
Core phosgenation reagent	32315-10-9	T103041	Triphosgene	≥99%	A classical solid phosgene equivalent that can be used for chloroformylation of alcohols/phenols, cyclization of diols to cyclic carbonates, carboxylic acid activation, preparation of isocyanates from primary amines, and synthesis of NCA monomers from amino acids. It is the core starting point for establishing triphosgene-based experimental routes.
Non-phosgene carbonylation control reagent	530-62-1	C109315	N,N'-Carbonyldiimidazole (CDI)	≥99%	Commonly used for carboxylic acid activation and acyl transfer. It is suitable for comparing triphosgene-based routes in terms of intermediate type, workup burden, and substrate compatibility in “activate first, then form the bond” strategies.
Acid chloride formation control reagent	79-37-8	O434200	Oxalyl chloride	Reagent grade, advanced pure, ≥99%	Commonly used for the rapid conversion of carboxylic acids into acid chlorides. It is suitable for comparison with triphosgene in terms of carboxylic acid activation rate, handling of volatile byproducts, and effects on sensitive substrates.
Acid chloride formation control reagent	7719-09-7	T433841	Thionyl chloride	Advanced pure, reagent grade, ≥99.5%, low iron	A classical reagent for converting carboxylic acids into acid chlorides. It is suitable for comparison with triphosgene in terms of acid chloride formation conditions, handling of gaseous byproducts, and operational differences in exothermic and moisture-sensitive systems.
Active carbonate construction reagent	74124-79-1	D106171	N,N'-Disuccinimidyl carbonate (DSC)	≥98%	Used to construct succinimidyl active carbonates. It can serve as a preformed activation-reagent control for triphosgene/NHS routes and is suitable for comparing in situ phosgenation with preformed activated-species strategies.
Activated ester component	6066-82-6	H109330	N-Hydroxysuccinimide (NHS)	≥98%	Commonly used to construct NHS active esters or active carbonates. It can serve as a control component between triphosgene in situ activation routes and preformed activated-species routes.
Preformed chloroformate control reagent	1885-14-9	P106536	Phenyl chloroformate	≥98%	A preformed chloroformate reagent suitable for comparison with routes in which triphosgene generates chloroformates in situ, and useful for screening carbonylation conditions for phenols, alcohols, or amines.
Amino-protecting chloroformate control reagent	501-53-1	B105737	Benzyl chloroformate	≥96%, contains 0.1% sodium carbonate as stabilizer	A classical reagent for introducing the Cbz (carbobenzyloxy) group. It can serve as a control for amino protection or carbamate construction via chloroformate intermediates generated from triphosgene.

Table 2 | Acid-Scavenging Bases, Catalysts, and Workup Control Components

Category	CAS No.	Aladdin Cat. No.	Name	Grade or Purity	Product Features and Applications
Aromatic amine-type acid-scavenging base	110-86-1	P111513	Pyridine	Anhydrous grade, ≥99.8%	A commonly used acid-scavenging base that can both absorb HCl and help organize chloroformylation of hydroxy substrates and diol cyclization conditions. It is a common starting point in basic condition screening for triphosgene reactions.
Conventional tertiary amine acid-scavenging base	121-44-8	T140677	Triethylamine	Anhydrous grade, ≥99.5%, Water ≤ 50 ppm	A commonly used tertiary amine base suitable for handling the HCl released in triphosgene reactions, and often used in routine condition setup for alcohol, amine, and carboxylic acid activation systems.
Hindered tertiary amine acid-scavenging base	7087-68-5	D109322	N,N-Diisopropylethylamine	Distilled grade, ≥99.5%	A more sterically hindered tertiary amine base, suitable when the goal is to reduce direct nucleophilic participation by the base itself. It is commonly used in condition screening for more sensitive substrates or reactive intermediates.
Tertiary amine acid-scavenging base	109-02-4	M104643	N-Methylmorpholine	Distilled grade, ≥99.5%	A common tertiary amine base that can be used in carbonylation, active ester construction, and some isocyanate-forming conditions. It is suitable for parallel comparison with triethylamine and DIPEA.
Hindered aromatic amine acid-scavenging base	108-48-5	L431380	2,6-Lutidine	Distilled grade, ≥99%	A sterically hindered aromatic amine base suitable when direct attack of the base on reactive intermediates should be reduced. It can be used to optimize selectivity and suppress side reactions.
Nucleophilic acyl-transfer catalyst	1122-58-3	D109207	4-Dimethylaminopyridine	≥99%	A nucleophilic acyl-transfer catalyst that can promote the subsequent conversion of chloroformates and active carbonates with alcohols/amines, and is suitable for accelerating carbonate or carbamate construction.
Workup/off-gas absorption base	1310-73-2	S111498	Sodium hydroxide	Guaranteed reagent, ≥96%	Commonly used for off-gas absorption, neutralization of acidic byproducts, and alkaline washing during workup. It is very common in the safety organization and cleanup stages of triphosgene systems.

Table 3 | Task-Oriented Model Substrates: Hydroxy, Carboxylic Acid, Amine, and Amino Acid Types

Category	CAS No.	Aladdin Cat. No.	Name	Grade or Purity	Product Features and Applications
Simple carboxylic acid model substrate	64-19-7	A116166	Acetic acid	Guaranteed reagent, ≥99.5%	A simple aliphatic carboxylic acid model substrate suitable for examining the basic reactivity of triphosgene or control acid-chlorinating reagents in driving carboxylic acids into acid chlorides, anhydrides, or subsequent acyl-transfer intermediates.
Aromatic carboxylic acid model substrate	65-85-0	B433248	Benzoic acid	Suitable for synthesis	A typical aromatic carboxylic acid substrate suitable for comparing triphosgene, oxalyl chloride, and thionyl chloride in carboxylic acid activation, acid chloride formation, and subsequent derivatization.
Alcohol model substrate	100-51-6	B163018	Benzyl alcohol	Pharmaceutical grade, PharmPure™	A typical primary alcohol substrate suitable for examining chloroformate formation, carbonate construction, and the route leading to subsequent carbamate formation with amines in triphosgene systems.
1,2-Diol cyclization model substrate	107-21-1	E119700	Ethylene glycol	Anhydrous grade, ≥99.8%	A classical 1,2-diol model substrate suitable for establishing the basic conditions for triphosgene-promoted cyclization of diols into five-membered cyclic carbonates.
1,3-Diol cyclization model substrate	504-63-2	P432773	1,3-Propanediol	Suitable for synthesis	A typical 1,3-diol substrate suitable for examining triphosgene-promoted formation of six-membered cyclic carbonates and the influence of chain length changes on cyclization efficiency and selectivity.
Polyol model substrate	56-81-5	G755728	Glycerol	Anhydrous grade, UltraBio™, molecular biology grade, ≥99.5% (GC)	A polyol model substrate suitable for examining selective carbonylation of polyhydroxy substrates, stepwise protection, and control of overreaction in triphosgene systems.
Phenolic phosgenation model substrate	108-95-2	P100770	Phenol	≥99.5% (GC)	A typical phenolic substrate suitable for examining chloroformylation of phenolic hydroxyl groups in triphosgene systems, and further corresponding construction of carbonate derivatives. It can also be compared with preformed phenyl chloroformate routes to evaluate in situ phosgenation versus direct use of chloroformate reagents as two different ways of organizing the reaction.
Aromatic primary amine model substrate	62-53-3	A112119	Aniline	Standard for GC, ≥99.9% (GC)	A typical aromatic primary amine substrate suitable for examining reactivity and side-reaction control in triphosgene-promoted conversion of amines into isocyanates, ureas, or carbamates.
Aliphatic primary amine model substrate	100-46-9	B108477	Benzylamine	AR, ≥99%	A common aliphatic primary amine substrate suitable for examining the organization of conditions for forming isocyanates from primary amines and for their subsequent derivatization in triphosgene systems.
Alicyclic primary amine model substrate	108-91-8	C105033	Cyclohexylamine	Moligand™, Standard for GC, ≥99.5% (GC)	An alicyclic primary amine model substrate suitable for comparison with aniline and benzylamine in evaluating the reactivity and selectivity of different amine types in triphosgene systems.
Amino acid NCA precursor substrate	56-40-6	G432934	Glycine	UltraBio™, molecular biology grade, ultrapure grade, ≥99% (NT)	The simplest α-amino acid precursor, corresponding to the classical route for preparing Gly-NCA with triphosgene, and suitable for establishing a basic understanding of NCA monomer synthesis.

Table 4 | Dehydration-Route Precursors and Representative Intermediates/Products

Category	CAS No.	Aladdin Cat. No.	Name	Grade or Purity	Product Features and Applications
Isocyanide dehydration precursor	6343-54-0	N159287	N-Benzylformamide	≥98% (GC)	A typical N-substituted formamide substrate suitable for examining the pathway by which formamides undergo dehydration to isocyanides in triphosgene systems. It forms a clear precursor-product correspondence with benzyl isocyanide.
Aldoxime dehydration precursor	932-90-1	B768539	Benzaldoxime	≥95%, mainly the E isomer	A typical aldoxime dehydration precursor suitable for the triphosgene-promoted dehydration route to benzonitrile, and a representative model substrate for oxime-to-nitrile conversion.
Representative isocyanate product	3173-56-6	B133636	Benzyl isocyanate	≥99% (GC)	A representative isocyanate product corresponding to the typical endpoint in which a primary amine is converted into an isocyanate via phosgenation under the action of triphosgene.
Representative NCA product	2185-00-4	O132967	2,5-Oxazolidinedione	≥98%	Can serve as a representative glycine N-carboxyanhydride, corresponding to the classical route in which triphosgene mediates preparation of NCA monomers from α-amino acids.
Representative urea product	102-07-8	D106405	N,N'-Diphenylurea	≥98%	Can serve as a representative urea product formed by further conversion of aromatic amines through isocyanate intermediates, and is suitable for understanding the downstream convergence of triphosgene-promoted carbonylation of amines.
Representative nitrile product	100-47-0	B119686	Benzonitrile	Anhydrous grade, ≥99%	A representative nitrile product suitable for corresponding result assignment in routes where precursors such as benzaldoxime are converted into nitriles under triphosgene dehydration conditions.
Representative isocyanide product	10340-91-7	B153177	Benzyl isocyanide	≥96% (GC)	A representative isocyanide product corresponding to the typical endpoint in which N-benzylformamide-type substrates are dehydrated to isocyanides under triphosgene conditions.

Note: The products listed above are representative Aladdin products. For more product specifications, please refer to the product list at the end of the article or search the Aladdin website using the “product name/CAS/catalog number.”

References

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[2] Wilder R, Mobashery S. The Use of Triphosgene in Preparation of N-Carboxy-α-amino Acid Anhydrides. The Journal of Organic Chemistry. 1992;57(9):2755-2756. doi:10.1021/jo00035a044.

[3] Burk RM, Roof MB. A Safe and Efficient Method for Conversion of 1,2- and 1,3-Diols to Cyclic Carbonates Utilizing Triphosgene. Tetrahedron Letters. 1993;34(3):395-398. doi:10.1016/0040-4039(93)85085-B.

[4] Charalambides YC, Moratti S. Comparison of Base-Promoted and Self-Catalyzed Conditions in the Synthesis of Isocyanates from Amines Using Triphosgene. Synthetic Communications. 2007;37(6):1037-1044. doi:10.1080/00397910601055156.

[5] Cotarca L, Geller T, Répási J. Bis(trichloromethyl)carbonate (BTC, Triphosgene): A Safer Alternative to Phosgene? Organic Process Research & Development. 2017;21(9):1439-1446. doi:10.1021/acs.oprd.7b00220.

[6] Ganiu MO, Nepal B, Van Houten JP, Kartika R. A Decade Review of Triphosgene and Its Applications in Organic Reactions. Tetrahedron. 2020;76(47):131553. doi:10.1016/j.tet.2020.131553.

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