Concurrent resolution and oxidation of an allylic acetate and its utilization in the diastereocontrolled synthesis of some cyclopentanoid monoterpenes
作者:Hiroshi Nagata、Kunio Ogasawara
DOI:10.1016/s0040-4039(99)01321-0
日期:1999.9
Racemic endo-4-acetoxybicyclo[3.2.1]oct-2-ene furnishes enantiopure (+)-bicyclo[3.2.1]oct-3-en-2-one and its dihydro derivative leaving enantiopure (+)-endo-4-acetoxybicyclo[3.2.1]oct-2-ene in a phosphate buffer solution in the presence of a lipase (Candida antarctica) and palladium(II) chloride. Utilizing the products, a diastereocontrolled route to some cyclopentanoid monoterpenes has been established
Diastereodivergent synthesis the C9-cyclopentanone chiral building block, serving as the non-tryptamine moiety of the Corynanthe type indole alkaloids and the related natural products, and its diastereomer has been developed from racemic norcamphor by employing lipase-mediated resolution via an allylic acetate intermediate having a bicyclo[3.2.1]octane framework. A potential of the latter diastereomer has been demonstrated by its conversion into (-)-semburin, a monoterpene isolated from Swertia japonica previously and obtained from the C9-block.
(+)-Juvabione and (+)-epijuvabione, natural sesquiterpenes exhibiting insect juvenile hormone activity, have been synthesized from (+)-norcamphor via the both enantiomeric intermediates having bicyclo[3.2.1]octane framework by employing a lipase-mediated kinetic ester-hydrolysis reaction and cyclopropane ring-expansion reaction as the key steps. (C) 1999 Elsevier Science Ltd. All rights reserved.