B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-Catalyzed Hydrogenation of Oxime Ethers without Cleavage of the NO Bond
作者:Jens Mohr、Martin Oestreich
DOI:10.1002/anie.201407324
日期:2014.11.24
The hydrogenation of oximes and oxime ethers is usually hampered by NO bond cleavage, hence affording amines rather than hydroxylamines. The boron Lewis acid B(C6F5)3 is found to catalyze the chemoselective hydrogenation of oxime ethers at elevated or even room temperature under 100 bar dihydrogen pressure. The use of the triisopropylsilyl group as a protecting group allows for facile liberation of
肟和肟醚的氢化通常受到NO键断裂的阻碍,因此提供的是胺而不是羟胺。发现硼路易斯酸B(C 6 F 5)3在升高的或什至在室温下在100巴的二氢压力下催化肟醚的化学选择性氢化。使用三异丙基甲硅烷基作为保护基可以容易地释放出游离的羟胺。
On the Origins of Diastereoselectivity in the Alkylation of Enolates Derived from <i>N</i>-1-(1′-Naphthyl)ethyl-<i>O</i>-<i>tert</i>-butylhydroxamates: Chiral Weinreb Amide Equivalents
作者:Stephen G. Davies、Christopher J. Goodwin、David Hepworth、Paul M. Roberts、James E. Thomson
DOI:10.1021/jo902499s
日期:2010.2.19
The stereochemical outcome observed upon alkylation of enolates derived from N-1-(1′-naphthyl)ethyl-O-tert-butylhydroxamates (chiral Weinreb amide equivalents) may be rationalized by a chiral relay mechanism. Deprotonation with KHMDS leads to a nonchelated (Z)-enolate in which the oxygen atoms adopt an anti-periplanar conformation. The configuration of the N-1-(1′-naphthyl)ethyl group dictates the