Shorter and Easier Syntheses of Di-tert-butylketene and Related gem-Di-tert-butyl Compounds
作者:Rudolf Knorr、Karsten-Olaf Hennig、Bernhard Schubert、Petra Böhrer
DOI:10.1002/ejoc.201000888
日期:2010.12
The ketene tBu 2 C=C=O is prepared from tBu 2 C=O in three steps (performable as a two-stage operation) through elimination of HCl from the intermediate product tBu 2 CCl-CH=O. The acid tBu 2 CH-CO 2 H, obtainable in two, three, or four preparative stages from tBu 2 C=O, adds slowly to the ketene to produce the anhydride (tBu 2 CH-CO) 2 O. Elemental lithium together with ClSiMe 3 converts tBu 2 CCl-CH=O
乙烯酮tBu 2 C=C=O是通过从中间产物tBu 2 CCl-CH=O中除去HCl分三步(可作为两阶段操作进行)由tBu 2 C=O制备的。酸 tBu 2 CH-CO 2 H 可从 tBu 2 C=O 在两个、三个或四个制备阶段中获得,缓慢添加到乙烯酮中以产生酸酐 (tBu 2 CH-CO) 2 O。元素锂与ClSiMe 3 将 tBu 2 CCl-CH=O 转化为 tBu 2 C=CH-OSiMe 3 ,这是 tBu 2 CH-CH=O 的耐用前体,使得这种醛可以从 tBu 2 C=O 中轻松且廉价地获得。通过排除其他可能的机制,tBuMgCl 对 tBu 2 CCl-CH=O 的还原显示出至少涉及一个单电子转移,导致烯醇化 tBu 2 C=CH-OMgCl,它可以转化为 tBu 2 CH-CH=O(从 tBu 2 C=O 三个步骤)或进入 tBu 2 C=CH-OSiMe 3 。从 NaBH