苯并啉缩合,Benzoin Condensation.
苯甲醛缩合是两个醛之间的偶联反应，可以制备α-羟基酮。第一种方法仅适用于芳香醛的转化。
苯并啉缩合反应机理
加入氰化物离子产生氰醇会影响正常的羰基电荷亲和性，而亲电性醛碳在脱脱去巯基后变得亲核：噻唑盐也可用作该反应的催化剂(参见Stetter反应)。
一个强碱现在能够在以前的羰基C-原子上脱羰基：
第二当量的醛与该碳离子反应，催化剂消除在反应结束时再生羰基化合物：
相关反应
斯特特反应
Related Reactions
Stetter Reaction
Recent Literature 近期文献
Chemoselective N-Heterocyclic Carbene-Catalyzed Cross-Benzoin Reactions: Importance of the Fused Ring in Triazolium Salts
S. M. Langdon, M. M. D. Wilde, K. Thai, M. Gravel, J. Am. Chem. Soc., 2014, 136, 7359-7542.
Lanthanum Tricyanide-Catalyzed Acyl Silane-Ketone Benzoin Additions
J. C. Tarr, J. S. Johnson, Org. Lett., 2009, 11, 3870-3873.
Kinetic Control in Direct α-Silyloxy Ketone Synthesis: A New Regiospecific Catalyzed Cross Silyl Benzoin Reaction
X. Linghu, J. S. Johnson, Angew. Chem. Int. Ed., 2003, 42, 2534-2536.
Highly Enantioselective Benzoin Condensation Reactions Involving a Bifunctional Protic Pentafluorophenyl-Substituted Triazolium Precatalyst
L. Baragwanath, C. A. Rose, K. Zeitler, S. J. Connon, J. Org. Chem., 2009, 74, 9214-9217.
An Efficient Nucleophilic Carbene Catalyst for the Asymmetric Benzoin Condensation
D. Enders, U. Kallfass, Angew. Chem. Int. Ed., 2002, 41, 1743-1745.