Amination of N-aryl prolinol via ring expansion and contraction: application to the chiral ligand for the catalytic asymmetric reaction.

Takashi Mino, Akio Saito, Youichi Tanaka, Shintaro Hasegawa, Yutaka Sato, Masami Sakamoto, Tsutomu Fujita

Index: J. Org. Chem. 70(5) , 1937-40, (2005)

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Abstract

Chiral diaminophosphines 4 were prepared from (S)-prolinol-derived aminophosphine oxide 5 by bromination with ring expansion followed by amination with ring contraction and reduction, using trichlorosilane. In the presence of 4 as a ligand, palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate (11) with a dialkyl malonate-BSA-LiOAc system was successfully carried out with good enantioselectivities (up to 98% ee).