HIGHLY EFFECTIVE AND PRACTICAL ENANTIOSELECTIVE SYNTHESIS OF HALF-ESTERS OF BICYCLO[2.2.1]HEPTANEDICARBOXYLIC ACID

An effective and practical enantioselective synthesis of half-esters of bicyclo[2.2.1]heptane-2,3-dicarboxylic acid was developed by enantioselective fission of sigma-symmetrical cyclic anhydrides with chiral mandelic acid derivatives, followed by deprotection of the mandelate moiety, crystallization, and further modification. These half-esters are very attractive chiral building blocks for numerous natural products, and this new method makes possible their synthesis via common intermediates with high optical purity.