Catalytic enantioselective intermolecular cycloaddition of 2-diazo-3,6-diketoester-derived carbonyl ylides with alkynes and styrenes using chiral dirhodium(II) carboxylates

Dirhodium(II) tetrakis[N-tetrachlorophthaloyl-(S)-tert-leucinate], Rh-2(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.