Total Synthesis of the Hydroxyketone Kurasoin A Using Asymmetric Phase-Transfer Alkylation.

The total synthesis of the farnesyltransferase inhibitor kurasoin A has been achieved using a novel asymmetric phase-transfer-catalyzed glycolate alkylation reaction. 2,5-Dimethoxyacetophenone 7 with cinchonidinium catalyst 9 (10 mol %) and hydroxide base with pivaloyl benzyl bromide 8 provided S-alkylation product 10 in high yield (80−99%) and excellent enantioselectivity. Baeyer−Villiger oxidation, Weinreb amide formation, and benzyl Grignard addition to the TES-ether 17 gave the protected target. Lithium hydroxide and peroxide generated kurasoin A ([α]D +8.4°) without isomerization.