10.1016/j.tetlet.2004.09.025
The study presents a novel approach for constructing quaternary centers on cycloalkane rings, which is a significant challenge in synthetic chemistry. The researchers utilized a combination of Birch reduction-allylation and Cope rearrangement on o-anisic acid derivatives to synthesize 2-acyl-3-cyclohexenone derivatives. They successfully generated rearrangement substrates and achieved high yields of 2-cyclohexenone products through thermal equilibration in 1,2-dichlorobenzene. Notably, the Cope rearrangement of a specific substrate resulted in the formation of a new quaternary center with excellent yield, marking the first example of such synthesis on a cycloalkenone ring via Cope rearrangement. This method could serve as a powerful tool for creating substituted 2-cyclohexenones, offering a potentially versatile synthetic intermediate with potential for 1,3-chirality transfer and access to enantiomerically pure products.