Asymmetric catalysis of Nozaki-Hiyama allylation and methallylation with a new tridentate bis(oxazolinyl)carbazole ligand.
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.
Inoue
Masahiro
M
Department of Chemistry, School of Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan.
Suzuki
Takahiro
T
Nakada
Masahisa
M