A theoretical study on the alkene insertion step in Rh-Yanphos catalyzed hydroformylation

摘要

This paper studied the mechanism of the alkene insertion elementary step in the asymmetric hydroformylation(AHF)catalyzed by RhH(CO)2[(R,S)-Yanphos]using four alkene substrates(CH255CH–Ph,CH255CH–Ph–(p)–Me,CH255CH–C(55O)OCH3and CH255CH–OC(55O)–Ph,abbreviated as A1–A4).Interestingly,the equatorial vertical coordination mode(A mode)with respect to the Rh center was found for A1 and A2 but not for A3 and A4,although the equatorial in-plane coordination mode(E mode)was found for A1–A4.The relative energy of the E mode of the h2-intermediates is lower than that of the A mode.In the alkene insertion step,Path 1 is more favorable than Path 2 for this system.As for A1 and A2,there could be a transformation between 2eq and 2ax.