Efficient, scalable asymmetric synthesis of an epoxy quinol via Noyori desymmetrization of a meso diketone

Epoxy quinol la was prepared on a multi-gram scale by Noyori transfer hydrogenative desymmetrization of the readily available meso-epoxy diketone 4. Although the intrinsic enantioselectivity for the desymmetrization was modest (82:18 er at 4% conversion), a highly enantiopure product (99.6:0.4 er) could be obtained in one operation in 44% yield via kinetic resolution of the minor enantiomer with long reaction times (48 h), or in 73% yield by combination with an enzymatic resolution of a 93:7 er mixture. (C) 2011 Elsevier Ltd. All rights reserved.