Efficient Synthesis of β-Hydroxy-α-Amino Acid Derivatives via Direct Catalytic Asymmetric Aldol Reaction of α-Isothiocyanato Imide with Aldehydes

✍ Scribed by Xiaohong Chen; Yin Zhu; Zhen Qiao; Mingsheng Xie; Lili Lin; Xiaohua Liu; Xiaoming Feng

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 303 KB
• Volume: 16
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.201000284

✦ Synopsis

Abstract

An easily available and efficient chiral N,N′‐dioxide–nickel(II) complex catalyst has been developed for the direct catalytic asymmetric aldol reaction of α‐isothiocyanato imide with aldehydes which produces the products in morderate to high yields (up to 98 %) with excellent diastereo‐ (up to >99:1 d.r.) and enantioselectivities (up to >99 % ee). A variety of aromatic, heteroaromatic, α,β‐unsaturated, and aliphatic aldehydes were found to be suitable substrates in the presence of 2.5 mol % L‐proline‐derived N,N′__‐__dioxide L5–nickel(II) complex. This process was air‐tolerant and easily manipulated with available reagents. Based on experimental investigations, a possible transition state has been proposed to explain the origin of reactivity and asymmetric inductivity.