Stereoselective synthesis of 2,3,4,5 tetrasubstituted tetrahydrofurans: Application to the total synthesis of (+)-Virgatusin and b) asymmetric radical additions to chiral sulfinimines

AEI 79

Tito Akindele, tito@pharm.kyoto-u.ac.jp1, Stephen P. Marsden, S.P.Marsden@leeds.ac.uk2, John G. Cumming, john.cumming@astrazeneca.com3, Ken-ichi Yamada1, and Kiyoshi Tomioka1. (1) Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan, (2) School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom, (3) Respiratory and Inflammation Research Area, AstraZeneca, Mereside, Alderley Park, Macclesfield, Cheshire, SK10 4TG, United Kingdom
a) Families of bioactive natural products such as lignans, eunicellins, and briarellins, contain the synthetically challenging 2,3,4,5-tetrasubstituted tetrahydrofuran (THF) motif. The enantioselective synthesis of tetrasubstituted THFs in modest to excellent yields with good to excellent diastereoselectivities via condensation of readily available, enantiomerically enriched allylsiloxanes with aldehydes, in the presence of a Lewis acid, will be described. Also, a concise, protecting group free, total synthesis of the lignan compound (+)-virgatusin as well as syntheses of the 6,5-cis-fused ring systems of the eunicellins and briarellins will be presented.

    

b) Addition of radical species to sulfinimines either in racemic or asymmetric fashion is relatively unexplored. As part of our ongoing interest in radical reactions, we will be describing a dimethylzinc-air initiated asymmetric radical addition of ethers to enantiopure sulfinimines in high yields (up to 92%) with high enantiocontrol (up to 92% ee).     

   

 

Academic Employment Initiative
8:00 PM-10:00 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Sci-Mix

Academic Employment Initiative

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007