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Asymmetric Catalysis of the [5 + 2] Cycloaddition Reaction of Vinylcyclopropanes and π-Systems

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posted on 17.05.2006, 00:00 by Paul A. Wender, Lars O. Haustedt, Jaehong Lim, Jennifer A. Love, Travis J. Williams, Joo-Yong Yoon
As part of our studies of metal-catalyzed [m + n (+...o)] cycloadditions, we have previously reported the rhodium-catalyzed [5 + 2] cycloaddition of vinylcyclopropanes (VCPs) and π-systems. These studies have led to Rh(I) complexes that catalyze these reactions in minutes at room temperature or in water without organic solvents. We describe a comparative evaluation of several chiral catalysts for the [5 + 2] reaction, evaluation of a preferred catalyst, [((R)-BINAP)Rh]+SbF6-, with substrates differing in substitution and tether typesproducing enantiomeric excesses ≥95% for several systems. A predictive model for the selectivity is also presented.