Catalytic asymmetric synthesis of Japonilure and its enantiomer

A mild, concise, and highly enantioselective (93% ee) synthesis of Japonilure and its enantiomer, Anomala osakana pheromone, is described. The key steps involve the asymmetric addition of methyl propionate to undec-2-ynal with a Zn-ProPhenol catalyst and the selective and partial reduction of the diynol ester to the cis-enol ester with Brown’s P2-Ni catalyst, providing the first synthesis of the enol ester via semi-hydrogenating diynol ester.

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(R,Z)-5-(Dec-1-en-1-yl)dihydrofuran-2(3H)-oneC14H24O2Ee = 93%[α]D25 = −69.3 (c 1.01, CHCl3)Source of chirality: (R,R)-ProPhenolAbsolute configuration: (R)