ORGN 554 |
| Propionate and polypropionate subunits are common structural motifs found in many biologically active natural products. Due to the prevalence of these subunits, intense and widespread research into their efficient, asymmetric formation has been conducted. Utilizing the cinchona alkaloid catalyzed acyl halide-aldehyde cyclocondensation (AAC) reaction developed by our group we were able to synthesize various polypropionate subunits in a facile and efficient manner. Aldehydes containing alpha-chiral, beta-chiral and both alpha- and beta-chiral stereocenters performed well, yielding optically active beta-lactones in good to excellent yields (65%-90%) with excellent diastereoselectivity (d.r. = from 10:1 to single diastereomer). These stereoenriched beta-lactones, which are masked aldol products, can serve as platforms for a variety of transformations. The application of this methodology towards the first catalytic, asymmetric total synthesis of discodermolide will also be discussed.
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Asymmetric Reactions and Syntheses
1:00 PM-5:00 PM, Wednesday, 31 August 2005 Washington DC Convention Center -- 201, Oral
Division of Organic Chemistry |
