Asymmetric Hydrogenation of γ-Branched Allylamines for the Efficient
Synthesis of γ-Chirogenic Amines
Abstract
The efficient construction of γ-chirogenic amines has been realized via
asymmetric hydrogenation of γ-branched N-phthaloyl allylamines by using
a bisphosphine-Rh catalyst bearing a large bite angle. The desired
products possessing different types of γ-substituents were obtained in
quantitative yields and with excellent enantioselectivities (up to
>99.9% ee). This protocol provided a practical method for
the preparation of γ-chirogenic amine derivatives such as the famous
antidepressant drug Fluoxetine (up to 50000 S/C). The mechanism
calculation shows a weak interaction-promoted activation mode which is
completely different from the traditional coordination-promoted
activation mode in the Rh-catalyzed hydrogenation.