SmI2-promoted Reformatsky-type coupling reactions in exceptionally hindered contexts.
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.
Sparling
Brian A
BA
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Moslin
Ryan M
RM
Jamison
Timothy F
TF
D012493:Samarium / Q000737:chemistry*; D013237:Stereoisomerism
D012493:Samarium