Organic Letters 2007-01-18

Asymmetric hydrogenation of alpha-chloro aromatic ketones catalyzed by eta6-arene/TsDPEN-ruthenium(II) complexes.

Takeshi Ohkuma, Kunihiko Tsutsumi, Noriyuki Utsumi, Noriyoshi Arai, Ryoji Noyori, Kunihiko Murata

Index: Org. Lett. 9(2) , 255-257, (2007)

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Abstract

Asymmetric hydrogenation of various alpha-chloro aromatic ketones with Ru(OTf)(TsDPEN)(eta6-arene) (TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine) produces the chiral chlorohydrins in up to 98% ee. This reaction can be conducted even on a 206-g scale. The hydrogenation of an alpha-chloro ketone with a phenol moiety has been utilized for the synthesis of (R)-norphenylephrine without protection-deprotection operations. [reaction: see text].