Alkoxy Radical Cyclizations onto Silyl Enol Ethers Relative to Alkene Cyclization, Hydrogen Atom Transfer, and Fragmentation Reactions
作者:Montserrat Rueda-Becerril、Joe C. T. Leung、Christine R. Dunbar、Glenn M. Sammis
DOI:10.1021/jo200992m
日期:2011.10.7
chemoselectivity of alkoxy radical cyclizations onto silyl enol ethers compared to competing cyclizations, 1,5-hydrogen atom transfers (1,5-HATs), and β-fragmentations. Cyclization onto silyl enol ethers in a 5-exo mode is greatly preferred over cyclization onto a terminal alkene. The selectivity decreases when any alkyl substitution is present on the competing alkene radical acceptor. Alkoxy radical 5-exo cyclizations