Simple and Mild Synthesis of Bis‐CF ₃ ‐Cyclobutane Derivatives via Photoinduced Regioselective Dimerization of 1,3‐Enynes

Cyclobutane derivatives are versatile structural motifs in natural products, pharmaceuticals. Cyclobutanes obtained from 1,3‐enynes are rare and suffer from poor yield, low chemoselectivity, and regioselectivity. Herein, we disclose a simple and mild synthesis of bis‐CF 3 ‐cyclobutanes via photoinduced chemoselective and regioselective head‐to‐head dimerization of β ‐CF 3 ‐1,3‐enyne with the alkynyl group intact. No head‐to‐tail dimerization isomers were observed. This reaction features simple and mild conditions, readily available substrates, good regioselectivity, broad substrate scope, and high functional group tolerance. This reaction was applied successfully to the late‐stage modification of drugs and natural products.