Organocatalysis by bimacrocyclic NHCs: unexpected formation of a cyclic hemiacetal instead of a γ-butyrolactone
作者:Ole Winkelmann、Christian Näther、Ulrich Lüning
DOI:10.1039/b815828b
日期:——
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.