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 σ-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