Highly syn-selective hydrogen-mediated aldol coupling of vinyl ketones catalyzed by rhodium

ORGN 491

Susan A Garner, sagarner@mail.utexas.edu and Michael J Krische, mkrische@mail.utexas.edu. Department of Chemistry and Biochemistry, University of Texas at Austin, 1 University Station, Welch Hall A5300, Austin, TX 78712-0165
Catalytic hydrogenation of commercially available methyl vinyl ketone (MVK) and ethyl vinyl ketone (EVK) in the presence of diverse aldehydes at ambient temperature and pressure using tri-2-furyl phosphine ligated rhodium catalysts enables formation of aldol products with exceptional levels of syn-diastereoselectivity. A progressive increase in diastereoselectivity is observed upon systematic replacement of phenyl residues for 2-furyl residues (Ph3P, FurPh2P, Fur2PhP, Fur3P). These studies represent the first highly diastereoselective reductive aldol additions involving vinyl ketones and provide regio- and stereoselectivities comparable to, or rivaling, those observed in low temperature reactions of preformed lithium enolates.

 

Metal-Mediated Reactions and Syntheses
1:00 PM-5:00 PM, Wednesday, 29 March 2006 Georgia World Congress Center -- C302, Oral

Division of Organic Chemistry

The 231st ACS National Meeting, Atlanta, GA, March 26-30, 2006