Catalytic Enantioselective Intermolecular Cycloaddition of 2-Diazo-3,6-diketoester-Derived Carbonyl Ylides with Alkynes and Styrenes Using Chiral Dirhodium(II) Carboxylates

Abstract
Dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh2(S-TCPTTL)4, is an exceptionally effective catalyst for enantioselective tandem carbonyl ylide formation−cycloaddition reactions of 2-diazo-3,6-diketoesters with arylacetylene, alkoxyacetylene, and styrene dipolarophiles, providing cycloadducts in good to high yields and with enantioselectivities of up to 99% ee as well as with perfect exo diastereoselectivity for styrenes.