A new synthetic method for (4R,6S)-4-t-butoxycarbonylmethyl-6-hydroxymethyl-2,2-dimethyl- 1,3-dioxane was accomplished by a chemoenzymatic approach. Racemic 4-(4-methylbenzyloxy)-3-hydroxybutyronitrile (3) was firstly synthesized via condensation and epoxy opening reactions. (S)-4- (4-Methylbenzyloxy)-3-hydroxybutyronitrile (4) was obtained from resolution of racemic 3 by the lipase from Artgribacter sp. with a high enantiomeric excess (98% ee) in the mixture solvent of acetonitrile/hexane (V∶V＝1∶4). Dihydroxy ester 7 was synthesized by a syn-selective triethylborane mediated reduction with a de value of 97%. Af-ter acid-catalyzed protection of 7 and hydrogenolysis of the benzyl protecting group, the objective 9 was obtained with a high optical purity.

Key words: chemoenzymic synthesis, enzymatic resolution, triethylborane, statins