Michael-Addition-Triggered Release of Substituents from Tertiary Amines

A general and operationally simple method for removing substituents from tertiary amines via Michael-addition-triggered carbocation release is described. Using methyl propiolate, hexafluoroisopropyl alcohol (HFIP), and thioanisole, this reaction enables efficient, metal-free cleavage of challenging groups─including benzyl, <i>p</i>-methoxybenzyl (PMB), allyl, propargyl, diphenylmethyl, and <i>tert</i>-butyl. This carbocation-mediated platform offers predictable, broad-scope amine deprotection and provides a practical alternative to hydrogenolysis and other redox-based protocols.