Two bimacrocyclic imidazolinium salts of different size, precursors to respective NHCs (N-heterocyclic carbenes), were tested as precatalysts in the reaction of aromatic aldehydes or ketones with enals. The expected lactones were produced in most cases, but in the reaction of methyl 4-formylbenzoate with cinnamaldehyde, the larger bimacrocycle led to the formation of a cyclic hemiacetal, while the smaller bimacrocycle gave the anticipated lactone.
在芳香醛或酮与烯醛的反应中,测试了作为各自 NHC(N-杂环碳烯)前体的两种不同大小的双环
咪唑啉盐作为前催化剂。在大多数情况下都产生了预期的内酯,但在 4-甲酰基
苯甲酸甲酯与
肉桂醛的反应中,较大的双环导致形成环状
半缩醛,而较小的双环则产生了预期的内酯。