(R)-2,3-O-Cyclohexylideneglyceraldehyde, a Versatile Intermediate for Asymmetric Synthesis of Homoallyl and Homopropargyl Alcohols in Aqueous Medium

Zn-mediated allylation and propargylation of (R)-2,3-O-cyclohexylideneglyceraldehyde (1) in aqueous medium following Luche's procedure afforded the anti homoallylic 3 and homopropargylic 8 alcohols in good yield and with high stereoselectivity. Crotylation of 1 under similar conditions afforded appreciable amounts of erythro-5 and threo-6 alcohols. In each case, the diastereo alcohols are separable by column chromatography. Compound 8 on appropriate chemical manipulation of its functionalities gave the (S)-enantiomer of (R)-13, a useful synthon of LTB(4). Compound 3 on chemical elaboration afforded a diversely functionalized triol derivative 15, a potentially useful synthon for many bioactive compounds.