Regio- and enantioselective bioreduction of methyleneketoesters using both polymeric resin and cellulose matrix

Methyleneketoesters were prepared in >90% yield by performing an IBX oxidation of Morita-Baylis-Hillman adducts. A methodology was developed to achieve methyl 3-aryl-3-keto-2-methylenepropanoate reduction using a screening of yeast strains in three different reaction procedures to obtain products with both high yield and diastereoselectivity. The reactions conducted in water provided inferior yields (50%) for substrates 2b-c. Employing Amberlite (R) XAD7HP which was a substrate reservoir that also immediately extracted the products from the reaction medium after their formation, syn-4a-c and anti-4a-c were isolated in 60-70% yield, with high stereoselectivity (98-99% ee). The best results were obtained using substrates adsorbed on filter paper which provided products yields above 70%, a 99% ee and a diastereomoeric ratio (syn-4: anti-4) 9:1. Cellulose matrix has excellent potential to be successfully employed in general biocatalytic reactions. (C) 2013 Elsevier B.V. All rights reserved. (AU)