Orientation in the Crossed Aldol Condensation of Chloral with Unsymmetrical Aliphatic Ketones
作者:Eberhard Kiehlmann、Pui-Wah Loo
DOI:10.1139/v71-260
日期:1971.5.15
in the crossed aldol condensation with chloral has been studied in glacial acetic acid and in dimethoxyethane. The reaction is irreversible and not accompanied by dehydration of the resulting 1,1,1-trichloro-3-hydroxy-4-alkanones. Except for butanone, condensation occurs preferentially at the least-hindered position of an unsymmetrical ketone. The α-methyl/α-methylene condensation product ratio obtained
在冰醋酸和二甲氧基乙烷中研究了一系列 14 种脂肪族酮在与氯醛的交叉羟醛缩合反应中的反应性。该反应是不可逆的,并且不伴随所得 1,1,1-三氯-3-羟基-4-烷酮的脱水。除丁酮外,缩合优先发生在不对称酮的受阻最少的位置。当使用乙酸钠作为催化剂时,由通式 RCH2COCH3 的酮得到的 α-甲基/α-亚甲基缩合产物比率在乙酸中高于在二甲氧基乙烷中作为溶剂。甲基烷基酮烷基的空间大小和链长对 α-甲基对氯醛的反应性有显着影响。