Asymmetric Catalysis of Nozaki-Hiyama Allylation and Methallylation with A New Tridentate Bis(oxazolinyl)carbazole Ligand

J. Am. Chem. Soc., 125 (5), 1140 -1141, 2003. 10.1021/ja021243p S0002-7863(02)01243-X
Web Release Date: January 14, 2003

Asymmetric Catalysis of Nozaki-Hiyama Allylation and Methallylation with A New Tridentate Bis(oxazolinyl)carbazole Ligand

Masahiro Inoue, Takahiro Suzuki, and Masahisa Nakada*

Department of Chemistry, School of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan

mnakada@waseda.jp

Received October 3, 2002

Abstract:

This work describes the development of a new tridentate ligand effective for the asymmetric catalysis of Nozaki-Hiyama allylation and methallylation. Various aldehydes were allylated or methallylated with good enantioselectivity (86-96%), and a key intermediate of calcitriol lactone synthesis was also obtained with excellent diastereoselectivity (97% de, 91%). The enantioselective reaction catalyzed by this Cr-ligand complex is applicable to a broad range of aldehydes and has great potential for natural product synthesis. Another remarkable feature of this ligand is the stability of the Cr-ligand complex which was recovered after the enantioselective reaction and recycled twice without diminishing the enantioselectivity and yield.

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