Enzymatic desymmetrization of 1,1 '-methylenedi-[(1R,1 ' S,3R,3 ' S,5S,5 ' R)-3-hydroxy-8-oxabicyclo[3.2.1]-oct-6-ene-1-yl]: Novel precursors of long chain polyketides

meso-1,1'-Methylenedi[(1R,1'S,3R,3'S,5S,5'R)-3-hydroxy-S-oxabicyclo[3.2. 1]oct-6-ene-1-yl] 14 obtained through the [4+3]-cycloaddition of 2,T-methylenedifuran to oxyallyl cation, followed by reduction, has been desymmetrized by means of a lipase catalyzed transesterification to afford (1 S,3S,5S)-1-[(1 R,3R,5R)-3-hydroxy-8-oxabicyclo[3.2. 1]oct-6-en-yl]methyl)-8-oxabicyclo[3.2.1]loct-6-en-3-yl acetate (-)-15 (89% ee). This compound was transformed into aromatic ester derivatives for establishing the absolute configuration. (c) 2005 Elsevier Ltd. All rights reserved.