1, 1, 2‐Trifunctionalization of Terminal Alkynes by Radical Addition–Translocation–Cyclization–Trapping for the Construction of Highly Substituted Cyclopentanes. Issue 4 (20th November 2020)

• Record Type: Journal Article
• Authors: Yang, Youqing; Daniliuc, Constantin G.; Studer, Armido
• Is Part Of: Angewandte Chemie international edition. Volume 60:Issue 4(2021)
• Page Start: 2145
• Page End: 2148
• Publication Date: 2020-11-20
• Subjects: alkyne functionalization -- cascade cyclization -- hydrogen atom transfer -- radicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202011785
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Radical 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. Abstract : 1, 1, 2‐Trifunctionalization of terminal alkynes is achieved by a radical cascade reaction comprising an addition, translocation, cyclization, and trapping step. Substituted cylopentanes bearing the medicinally relevant CF3 ‐group along with the synthetically valuable alkynyl moiety are obtained. The method uses readily prepared alkynyl triflones as CF3 ‐radical precursors and as alkynylating reagents.