Abstract
Oxidative free-radical cyclization of α-chloromalonate 9 with Mn(OAc)3·2H2O and Cu(Oac)2·H2O in acetic acid at 75 °C provides 82% of lactones 10a and 10b. Hydroboration of 10 followed by oxidation affords acids 12, which are converted to avenaciolide precursor 15 in 32% overall yield from 9 by decarboxylation and cyclization.