Preparation and Reactions of Enantiomerically Pure α-Functionalized Grignard Reagents

2013 ◽  
Vol 135 (21) ◽  
pp. 8071-8077 ◽  
Author(s):  
Peter J. Rayner ◽  
Peter O’Brien ◽  
Richard A. J. Horan
Keyword(s):  
Grignard Reagents ◽  
Enantiomerically Pure

Stereospecific Grignard reactions of cholesteryl 1-alkenesulfinate esters: Application of the Andersen Protocol to the preparation of non-racemic α,β-unsaturated sulfoxides

2003 ◽  
Vol 81 (6) ◽  
pp. 423-430 ◽  
Author(s):  
Rick R Strickler ◽  
John M Motto ◽  
Craig C Humber ◽  
Adrian L Schwan
Keyword(s):  
Ester Group ◽  
Grignard Reagents ◽  
Grignard Reaction ◽  
Substitution Reactions ◽  
Reaction Conditions ◽  
Enantiomerically Pure ◽  
Sulfinate Esters ◽  
Grignard Reactions

Enantiomerically enriched α,β-unsaturated sulfinate esters of (–)-cholesterol undergo stereospecific substitutions at sulfur when treated in benzene at 6°C with Grignard reagents. Sulfoxides with ees of 85–99.5% are obtained when enantiopure sulfinates are used. The substitution reactions proceed with inversion of sulfur configuration. Enantiomerically pure cholesteryl (E)-2-carbomethoxyethenesulfinate is not a suitable reactant under the Grignard reaction conditions. It is suggested that the ester group induces unwanted reactions significantly lowering both the yield and sulfur stereogenicity.Key words: sulfinate, sulfoxide, Grignard reagents, stereospecific, unsaturated.

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