Catalysis of Organic Reactions by Carbenes and Carbene Complexes

Highly efficient carbene and polycarbene catalysis of the transesterification reaction

“…Examples include the work described in research reports 39,40 or in monographs 9,10 . However, a common feature of these mechanisms is the participation of carbenes that are connected to alcohols by means of H-bonds such as those in 1B or in azoline forms such as 1A, with which they are in equilibrium.…”

Synthesis and properties of heteroaromatic carbenes of the imidazole and triazole series and their fused analogues

“…[276][277][278] Several of the studies showed that some heterocyclic carbenes become unstable upon heating. 103,168,279 Interestingly, reactions of this type have not been studied until recently. 4.1.1.…”

“…It was later found 104,195,279,328 that benzimidazol-2-ylidene 20E, 1,3,4,5-tetraphenyl substituted imidazol-2-ylidene, and the soluble 1,2,4-triazol-5-ylidenes 42D are all easily inserted (at room temperature) into a C-H bond of acetonitrile thereby producing the corresponding azolines 74A-C (Scheme 74). Dibenzyl-and dimethyl-substituted benzimidazol-2-ylidenes react in situ in a similar fashion.…”

“…21,[394][395][396] Catalysis by carbenes had long been known and exploited. However, they were usually generated in situ which generally did not produce pure, isolable carbenes.…”

“…[8][9][10][11][12][13][14][15][16][17][18][19][20] One of the major focuses of carbene applications has been the catalysis of organic reactions. [21][22][23][24][25][26][27][28][29][30] The connection between individual carbene structure and function has been reported in many publications. However, there remains a considerable problem in that the leading structures in any particular area have not yet been well identified.…”