Cu(<scp>ii</scp>)-mediated direct intramolecular cyclopropanation of distal olefinic acetate: access to cyclopropane-fused γ-lactones
Yulong Wang, Shenyu Shen, Chonglong He, Youkang Zhou, Keyuan Zhang, Bin Rao, Tian Han, Yaqiong Su, Xin‐Hua Duan, Le Liu
Abstract
transition-metal catalysed intramolecular carbenoid insertion, which suffers from prefunctionalization of starting materials and limited substrate scope. Herein, we disclose a practical copper-mediated direct intramolecular cyclopropanation of distal olefinic acetate to synthesize cyclopropane-fused γ-lactones and lactams. This cascade reaction is postulated to proceed through a hydrogen atom transfer event induced radical cyclization and copper-mediated cyclopropanation sequence. The protocol features high atom- and step-economy, excellent diastereoselectivity, broad tolerance of functional groups, and operational simplicity.