SYNTHESIS OF BICYCLO[3.3.1]NONANES VIA MANGANESE(III) MEDIATED RADICAL CYCLIZATION OF OLEFINIC BETA-KETO-ESTERS

Oxidative cyclization of olefinic beta-keto esters 11 and 19 with Mn(O Ac)(3).2H(2)O and Cu(OAc)(2) . H2O gave 12 and 23, respectively. These products are formed by initial cyclization to a bicyclo[3.3.1]nonane radical which abstracts a hydrogen atom from the N-ethyl substituent o f a proximal amide. In the case of 19, a further cyclization of the re sultant radical leads to 22 which is oxidized to 23.