1,1,2‐Trifunctionalization of Terminal Alkynes by Radical Addition–Translocation–Cyclization–Trapping for the Construction of Highly Substituted Cyclopentanes

Abstract

AbstractRadical 1,1,2‐trifunctionalization of terminal alkynes by an addition–translocation–cyclization–trapping sequence using readily available alkynyl triflones as trifluoromethyl radical precursors and trapping reagents is reported. Cascades occur by addition of the trifluoromethyl radical to a terminal alkyne, 1,5‐hydrogen atom transfer, 5‐exo‐cyclization, and subsequent alkynylation to provide (1‐trifluoromethyl)propargyl cyclopentanes. Reactions proceed with commercial dibenzoyl peroxide or α,α′‐azobisisobutyronitrile as the initiator at elevated temperature and provide the highly substituted cyclopentanes in good yields.