About the Crystal Structure of [Rh((S,S)-DIPAMP)- ((Z)-2-benzoylamino-3-(3,4-dimethoxyphenyl)-methyl Acrylate)]BF4: Major or Minor Catalyst−Substrate Complex?

Abstract

Asymmetric hydrogenation of (Z)-2-benzoylamino-3-(3,4-dimethoxyphenyl)-methyl acrylate with [Rh((S,S)-DIPAMP)(MeOH)2]BF4 was investigated. Low temperature NMR measurements prove the recently published X-ray structure of [Rh((S,S)-DIPAMP)((Z)-2-benzoylamino-3-(3,4-dimethoxyphenyl)-methyl acrylate)]BF4 to be the major substrate complex. The asymmetric hydrogenation of the prochiral DOPA precursor with the cationic Rh-DIPAMP catalyst therefore follows the “anti-lock-and-key” motif analogue to similar substrate complexes already known from literature.