Department of Chemistry
Silver triflate catalyzed cyclopropyl carbinol rearrangement for benzo[b]oxepine and 2H-chromene synthesis
An efficient AgOTf-catalyzed (TfO = trifluoromethanesulfonate) cyclopropyl carbinol rearrangement for the synthesis of benzo[b]oxepines and 2H-chromenes is reported by starting from 2-[cyclopropyl(hydroxy)methyl]phenols. The reactions proved to be general in scope and furnished a range of the corresponding functionalized oxygen heterocycles. The formation of the benzo-fused six-membered adduct is proposed to result from the ring-contraction of the benzo[b]oxepine derivative. Control of the product selectivity is achievable by fine-tuning the reaction time. The catalytic synergy between the silver(I) cation and the triflate anion was essential for optimal product yields.
Homogeneous catalysis, Oxygen heterocycles, Rearrangement, Ring expansion, Silver
Source Publication Title
European Journal of Organic Chemistry
Link to Publisher's Edition
Chan, Philip Wai Hong, Wan Teng Teo, Shaun Wei Yong Koh, Bo Ra Lee, Benjamin James Ayers, Dik Lung Ma, and Chung-Hang Leung. "Silver triflate catalyzed cyclopropyl carbinol rearrangement for benzo[b]oxepine and 2H-chromene synthesis." European Journal of Organic Chemistry 2015.20 (2015): 4447-4456.