Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, USA.
J Am Chem Soc. 2012 Sep 19;134(37):15233-6. doi: 10.1021/ja306225u. Epub 2012 Sep 11.
α-Oxy amides are prepared through enantioselective synthesis using a sequence beginning with a Henry addition of bromonitromethane to aldehydes and finishing with Umpolung Amide Synthesis (UmAS). Key to high enantioselection is the finding that ortho-iodo benzoic acid salts of the chiral copper(II) bis(oxazoline) catalyst deliver both diastereomers of the Henry adduct with high enantiomeric excess, homochiral at the oxygen-bearing carbon. Overall, this approach to α-oxy amides provides an innovative complement to alternatives that focus almost entirely on the enantioselective synthesis of α-oxy carboxylic acids.
α-氧基酰胺通过使用从溴硝基甲烷对醛的Henry 加成开始并以反转酰胺合成(UmAS)结束的对映选择性合成来制备。高对映选择性的关键是发现手性铜(II)双恶唑啉催化剂的邻碘苯甲酸盐以高对映过量提供Henry 加合物的两种非对映异构体,在含氧碳上为同手性。总体而言,这种α-氧基酰胺的方法为几乎完全专注于α-氧基羧酸的对映选择性合成的替代方法提供了一种创新的补充。