THE FOUR-CARBON ELONGATION OF THREE-CARBON CHIRAL SYNTHONS USING 2-(TRIMETHYLSILOXY)FURAN: HIGHLY STEREOCONTROLLED ENTRY TO ENANTIOMERICALLY PURE SEVEN-CARBON α,β-UNSATURATED 2,3-DIDEOXYALDONOLACTONES

Article abstract of DOI:10.1016/S0040-4020(01)87777-2

The BF3-promoted addition of 2-(trimethylsiloxy)furan to three carbon synthons derived from D- and L-glyceraldehyde, D- and L-serinal, and imines thereof furnishes C7 α,β-unsaturated 2,3-dideoxy-aldonolactone derivatives in high yield, with very high level of diastereoselection.In all the cases, compounds having 4,5-threo:5,6-erythro relative stereodisposition preferentially emerge from the reactions, accompanied by only marginal amounts of 4,5-erythro:5,6-threo epimers.An empirical rule for the rapid assignment of the configuration at C-4 (γ-carbon) of γ-substituted unsaturated and saturated β-butyrolactones is given, based upon the sign of the optical rotation values.