Carbonylation of organomagnesium compounds: catalysis by hexamethylphosphoric triamide
作者:Wilhelmus J. J. M. Sprangers、Robert Louw
DOI:10.1039/p29760001895
日期:——
(hydroxy)ketone derivatives [(1), (4), and (5)] from primary alkyl halides are outlined. Other types of R(Mg)X mostly lead to acyloins RCH(OH)C(O)R. Evidence for the formation of RCOMgX, or equivalent(s), as ‘first’ intermediates is presented. The overall mechanism is discussed. Products, and effects of HMPT on rate and product composition, can satisfactorily be explained via nucleophilic addition and substitution
添加(或使用纯净的)六甲基磷酸三酰胺(HMPT)时,在醚中非常慢的格氏试剂衍生物(RMgX)的羰基化作用明显加快。通常情况下,室温和室温下几分钟内就可以完成CO的吸收。30个大气压 产物组成取决于R,溶剂组成(RMgX:HMPT比)以及亲电试剂(例如“额外的”烷基卤化物)的存在。概述了从伯烷基卤化物制备几种类型的(羟基)酮衍生物[(1),(4)和(5)]的合成方法。其他类型的R(Mg)X大多会产生酰化糖RCH(OH)C(O)R。提供了形成RCOMgX或等同物作为“第一”中间体的证据。讨论了整个机制。可以通过亲核加成和取代步骤,去质子化和还原反应令人满意地解释产物以及HMPT对速率和产物组成的影响,从而导致烯醇的Mg盐成为“最终”中间体。