Asymmetric synthesis of palitantin from the (5R)-tert-butyldimenthylsiloxy-2-cyclohexenone

Article abstract of DOI:10.1016/S0040-4039(99)01549-X

(+)-Palitantin (2) has been synthesized in 25% overall yield from the (5R)-tert-butyldimethylsiloxy-2-cyclohexenone [(R)-1] where a remarkable diastereoselective cat. OsO₄ cis-dihydroxylation of (R)-1 furnished the precursor of the optically pure (5R,6R)-bis-trimethylsiloxy 2-cyclohexenone (7) which underwent highly selectively the 1,4-addition reaction of the 1,3-heptadienyl cyanocuprate to give, after trapping of the corresponding copper enolate with formaldehyde, the target compound.