On the Mechanism of the Directed <i>ortho</i> and Remote Metalation Reactions of <i>N</i>,<i>N</i>-Dialkylbiphenyl 2-carboxamides
作者:David Tilly、Jian-min Fu、Bao-ping Zhao、Manlio Alessi、Anne-Sophie Castanet、Victor Snieckus、Jacques Mortier
DOI:10.1021/ol902268h
日期:2010.1.1
A study concerning the mechanism of the LDA-mediated ortho and remote metalation of N,N-dialkyl-2-biphenyl carboxamides (e.g., 4a) is reported. On the basis of site-selective lithiation/electrophile quench experiments, including deuteration, the LDA metalation of 4 is proposed to involve initial amide-base complexation (CIPE) and equilibrium formation of 5, whose fast reaction with an in situ electrophile
报道了关于LDA介导的N,N-二烷基-2-联苯羧酰胺(例如4a)的邻位和远程金属化的机理的研究。在包括氘化的位点选择性锂化/亲电淬灭实验的基础上,提出4的LDA金属化涉及初始酰胺基络合(CIPE)和5的平衡形成,其与原位亲电体(TMSCl)的快速反应提供6阻止其与7平衡。在没有亲电子试剂的情况下,5通过4a与7进行平衡,其命运是瞬间环化成稳定的四面体甲醇胺氧化物8,只有在水解时才能提供芴酮(3)。