Electronic and steric control of regioselectivities in Rh(I)-catalyzed (5+2) cycloadditions: experiment and theory

Density functional theory (DFT) is used for analyzing the regioselectivity of Rh(I)-catalyzed (5+2) cycloadditions between vinylcyclopropanes (VCPs) and alkynes. VCPs with substitution at the internal position of the alkene have reacted with variable regioselectivity, indicating a refined model in which electron-withdrawing substituents on the alkyne have decreased or reversed sterically controlled selectivity by stabilizing the transition state in which the substituent is proximal to the forming C-C bond.