Asymmetric hydroformylation catalyzed by an Rh(I)-(R, S)-BINAPHOS complex: substituent effects in olefins on the regioselectivity

Olefins bearing the larger substituents at the allylic position were hydroformylated in the higher iso/normal selectivity when Rh(I)-(R, S)-BINAPHOS was used as a catalyst. Deuterioformylation of 4,4,4-triphenyl-1-butene suggests that the higher iso/normal ratio may be attributed to the accelerated CO insertion to the iso-alkylrhodium 7i.