Organic letters

An improved lanthanum catalyst system for asymmetric amination: toward a practical asymmetric synthesis of AS-3201 (Ranirestat)

T Mashiko, N Kumagai, M Shibasaki

Index: Mashiko, Tomoyuki; Hara, Keiichi; Tanaka, Daisuke; Fujiwara, Yuji; Kumagai, Naoya; Shibasaki, Masakatsu Journal of the American Chemical Society, 2007 , vol. 129, # 37 p. 11342 - 11343

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Citation Number: 49

Abstract

A catalytic asymmetric amination with a lanthanum/amide complex was significantly improved. The use of lanthanum nitrate hydrate in place of lanthanum triisopropoxide made the process reproducible, scalable, and cost-effective. The development of a ternary catalytic system of La/ligand/amine was a key to high ee and catalytic turnover. A 100 g scale reaction was performed to showcase a practical synthesis of a key intermediate for AS- ...