Organic Letters 2008-03-20

SmI2-promoted Reformatsky-type coupling reactions in exceptionally hindered contexts.

Brian A Sparling, Ryan M Moslin, Timothy F Jamison

Index: Org. Lett. 10(6) , 1291-4, (2008)

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Abstract

Highly substituted, very hindered enones were synthesized using a two-step procedure that utilizes a diiodosamarium-promoted Reformatsky-type coupling and dehydration using Martin sulfurane. Both alpha-chloro- and alpha-bromoketones were coupled with a variety of carbonyl nucleophiles to form the intermediate beta-hydroxyketones, occurring with excellent diastereoselectivity, favoring the syn isomer (R1=Me). This technique complements other methods and enables the preparation of enones outside of the scope of current olefination methodology.