Abstract
Oxidative free radical cyclization of B-keto esters such as la with Mn(0Ac)3-2H20 and Cu(0Ac)2-H20 leads to bicyclic products such as 6a in excellent yield. The key steps are oxidation of la to 2a by Mn(0Ac)3-2H20, two successive free radical cyclizations to give 4a, and oxidative B-hydride elimination by Cu(0Ac)2-H20 to give 6a.