Enantioselective synthesis of cyclic dialkyl (3-hydroxy-1-alkenyl) phosphonates by baker's yeast-mediated reduction of the corresponding enones

Cyclic dialkyl (3-oxo-1-cycloalkenyl) phosphonates were subjected to baker' s yeast-mediated enantioselective reductions to afford the corresponding di alkyl (3-hydroxy-1-alkenyl) phosphonates. The six- and seven-membered ring enones were reduced with moderate to good enantiomeric excesses, whereas th e five-membered ring substrate always yielded the double bond reduced compo und. The use of different reduction conditions did not improve the ee's mar kedly, but it was found, for the six-membered analogues, that the alkyl gro ups held by phosphorus influence dramatically the enantioselectivity of the reduction, leading to up to 95% enantiomeric excess. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.