Alkyne migratory functionalization via C(sp³)-C(sp³) bond transposition.

Abstract

Different from broadly studied metal walking strategy as a powerful way to realize remote C-H activation of alkenes, process for alkyne walking and functionalization remains unexplored. Similarly, alkyne hydrofunctionalization exclusively focuses on in situ transformation, while related remote protocol is unknown. Here we describe a proof-of-concept study on migratory alkyne functionalization. Three types of alkynes and two types of nucleophiles are adopted to realize the migratory hydroalkylation and hydroamination of alkynes with good stereocontrol, which also represents a potential route for the asymmetric activation of three continuous inert C(sp³)-H bonds. Gram-scale test and downstream transformations highlight the reliability and practical value of the concept. Mechanistic studies including calculations uncover a featured 1,3-diene formation-driven allylic C(sp³)-C(sp³) bond transposition process, which enables the stereoconvergence of undesired regioisomers from competitive in situ hydrofunctionalization into consistent migration products.