Fischer Christian, Smith Sean W, Powell David A, Fu Gregory C
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Am Chem Soc. 2006 Feb 8;128(5):1472-3. doi: 10.1021/ja058222q.
N-Heterocyclic carbenes can catalyze beta-alkylations of a range of alpha,beta-unsaturated esters, amides, and nitriles that bear pendant leaving groups to form a variety of ring sizes. In this process, the nucleophilic catalyst transiently transforms the normally electrophilic beta carbon into a nucleophilic site through an unanticipated addition-tautomerization sequence.
N-杂环卡宾可以催化一系列带有侧链离去基团的α,β-不饱和酯、酰胺和腈的β-烷基化反应,以形成各种不同的环大小。在这个过程中,亲核催化剂通过一个意想不到的加成-互变异构序列,将通常具有亲电性的β-碳瞬间转化为一个亲核位点。