Stereoselective conjugate addition of aromatic thiols to cyclic α, β-unsaturated ketones using inexpensive transition metal chiral catalysts under mild and neutral conditions

ORGN 464

Alan G. Preston and Saeed Attar. Department of Chemistry, California State University, Fresno, M/S SB70, Fresno, CA 93740

Asymmetric conjugate additions of aromatic thiols to a, b-unsaturated ketones are important reactions in biochemistry, the synthesis of biologically active compounds and in the formation of useful synthetic intermediates. Methods for the stereoselective synthesis of b-(arylthio)-cyclohexanes are under investigation. Reactions using in-situ Ni and Co based chiral catalysts using (R)-(+) and (S)-(-)-1,1’-Binaphthyl-2,2’-diamine and (R,R)-(-) and (S,S)-(+)-N,N’-Bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine ligands under mild and neutral conditions are described. The determination of enantiomeric excess (% ee) in these reactions using chiral GC analysis will also be reported.

Total Synthesis, Asymmetric Reactions and Syntheses, Bioorganic 9:00 AM-11:00 AM, Wednesday, March 31, 2004 Anaheim Convention Center -- Hall C, Poster Division of Organic Chemistry The 227th ACS National Meeting, Anaheim, CA, March 28-April 1, 2004