Triphosgene

Triphosgene [Bis(trichloromethyl)carbonate] is a versatile organic reagent used in organic synthesis alternative to phosgene. A catalytic amount of triphosgene is particularly used in chloroformylations, carbonylations, chlorinations, and dehydration reactions.
It is also commonly employed as a coupling agent in the synthesis of carbonyl compounds.

Triphosgene can be employed as a reagent to prepare:

• Thiocarbonates from thiols and alcohols by one-pot, three-component reaction.
• Substituted azetidin-2-ones from acids and imines via ketene–imine cycloaddition reaction.
• Methyl (S)-2-isocyanato-3-phenylpropanoate from L-phenylalanine methyl ester hydrochloride in the presence of sodium bicarbonate.
• Acyl azides derivatives from various carboxylic acids and sodium azide.
• Immunosuppressant agent cyclosporin by solid-phase peptide synthesis.
• Allyl azides from allyl alcohols and sodium azide in one pot method.
• Esterification coupling reagent di-2-thienyl carbonate, from 2(5H)-thiophenone.
• 2-Chloronicotinaldehydes via cyclization of the corresponding enamides.