HFIP-promoted strain-release rearrangement/N-functionalization of azabicyclo[1.1.0]butanes with para-quinone methides for the synthesis of azetidines

Abstract

A metal-free and atom-economic methodology for the synthesis of N-alkyl-substituted azetidines through strain-release-driven rearrangement/N-alkylation of ABBs with p-QMs is reported, in which HFIP plays the key role acting as a dual activator. The direct N-alkylation of ABBs is rarely reported. Broad substrate scope and mild conditions demonstrate its practical advantages.