Mechanistic insights into the triazolylidene-catalysed Stetter and benzoin reactions: role of the N-aryl substituent

被引:114
作者
Collett, Christopher J. [1 ]
Massey, Richard S. [2 ]
Maguire, Oliver R. [2 ]
Batsanov, Andrei S. [2 ]
O'Donoghue, AnnMarie C. [2 ]
Smith, Andrew D. [1 ]
机构
[1] Univ St Andrews, Sch Chem, EaStCHEM, St Andrews KY16 9ST, Fife, Scotland
[2] Univ Durham, Univ Sci Labs, Dept Chem, Durham DH1 3LE, England
基金
英国工程与自然科学研究理事会;
关键词
HETEROCYCLIC CARBENE; ALPHA; BETA-UNSATURATED ALDEHYDES; TRIAZOLIUM SALTS; NUCLEOPHILIC-ADDITION; BRESLOW INTERMEDIATE; THIAZOLIUM SALTS; THIAMINE ACTION; UMPOLUNG; GENERATION; ACID;
D O I
10.1039/c2sc22137c
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The in situ observation, isolation and reversible formation of intermediate 3-(hydroxybenzyl) azolium salts derived from NHC addition to a range of substituted benzaldehydes is probed. Equilibrium constants for the formation of these 3-(hydroxybenzyl) azolium salts, as well as rate constants of hydrogen-deuterium exchange (k(ex)) at C(alpha) of these intermediates for a range of N-aryl triazolinylidenes is reported. These combined studies give insight into the preference of N-pentafluorophenyl NHCs to participate in benzoin and Stetter reaction processes.
引用
收藏
页码:1514 / 1522
页数:9
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