Alkoxy Radical Cyclizations onto Silyl Enol Ethers Relative to Alkene Cyclization, Hydrogen Atom Transfer, and Fragmentation Reactions

M Rueda-Becerril, JCT Leung, CR Dunbar…

Index: Rueda-Becerril, Montserrat; Leung, Joe C.T.; Dunbar, Christine R.; Sammis, Glenn M. Journal of Organic Chemistry, 2011 , vol. 76, # 19 p. 7720 - 7729

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Citation Number: 13

Abstract

This study examines the 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 ...