CHEMOENZYMATIC SYNTHESIS OF GLYCOSYLATED ENANTIOMERICALLY PURE 4-PENTENE 1,2-DIOL AND 1,3-DIOL DERIVATIVES

1-Dimethylthexylsiloxy-2-chloroacetoxy-4 2 and 1-dimethylthexylsiloxy- 3-chloroacetoxy-4-pentene 3 were saponified with Pseudomonas lipase to give (R)-1-dimethylthexylsiloxy-4-pentene-2-ol (ee=99%) and (S)-2 (ee =99%) and (S)-1-dimethylthexylsiloxy-4-pentene-3-ol (ee=99%) and (R)-3 (ee=98%), respectively. All enantiomers were chemically transformed i nto the corresponding enatiomerically pure 2-benzoyloxy-4-pentene-1-ol s 8 and 3-benzoyloxy-4-pentene-1-ols 14, respectively. Mannosylation o f (R)-8 and (S)-14 with 2,3,4,6-tetra-O-benzoyl-a-D-mannopyranosyl tri chloroacetimidate afforded the corresponding mannopyranosides. (C) 199 8 Elsevier Science Ltd. All rights reserved.