Cationic 1,2,3-Triazolium Alkynes: Components To Enhance 1,4-Regioselective Azide-Alkyne Cycloaddition Reactions

Org Lett. 2016 Feb 19;18(4):788-91. doi: 10.1021/acs.orglett.6b00055. Epub 2016 Feb 5.

Abstract

4-Alkynyl-1,2,3-triazolium cations undergo thermal [3 + 2] cycloaddition reactions with azides roughly 50- to 100-fold faster than comparable noncharged alkynes. Further, the reaction is highly 1,4-regioselective (dr up to 99:1) owing to the selective stabilization of 1,4-TS transition states via conjugative π-acceptor assistance of the alkyne triazolium ring. The novel cationic triazolium alkynes also accelerate the CuAAC reaction to provide bis(1,2,3-triazoles) in an "ultrafast" way (<5 min).

Publication types

  • Research Support, Non-U.S. Gov't