Biocatalytic stereoselective synthesis of pyrrolidine-2,3-diones containing all-carbon quaternary stereocenters

Highly functionalized pyrrolidine-2,3-diones can be synthesized efficiently and stereoselectively under mild conditions using a biocatalytic approach. The reaction led to the formation of new all-carbon quaternary stereocenters from Myceliophthora thermophila laccase (Novozym 51003) catalyzed oxidation of catechols to ortho -quinones and subsequent 1,4-addition with 3-hydroxy-1,5-dihydro-2 H -pyrrol-2-ones. The reaction was conducted with various substituents on both reactants, resulting in 13 products in moderate to good yields (42-91%). The same 15 reactions were also tested with K 3 Fe(CN) 6 as a catalyst, but here only one reaction resulted in a product (60% yield). The diastereoselective synthesis of all-carbon benzylic quaternary stereocenters via conjugate addition of pyrrolidinones to ortho -quinones catalyzed by laccase under mild reaction conditions is reported.