Use of comparative triazolinium triflate fragmentation rates as a tool to assay relative competency of Brønsted bases in N-->N proton transfer.

Brønsted acid-induced fragmentation of a triazoline is used as a tool to identify Brønsted base additives capable of playing the role of a proton shuttle. Relative to water, dimethyl formamide accelerates proton transfer substantially under these conditions. A series of alcohols and ethers were also used to demonstrate that the Brønsted basicity of additive functionality, not their Brønsted acidity, is responsible for their ability to accelerate proton transfer from triazoline N3 to N1. This knowledge was then used to develop a convenient two step protocol for the synthesis of oxazolidine diones from benzyl azide and an unsaturated imide that employs a substoichiometric additive for triazolinium fragmentation.