Experimental and theoretical investigation of the scope of enantioselective ketone allylations employing Nakamura’s allylzinc–bisoxazoline reagent

The scope of enantioselective allylations employing Nakamura’s allylzinc–bisoxazoline reagent was examined by performing allylations of a selection of readily available ketones. Low-to-moderate ee’s were observed, and a computational study was conducted to rationalize the results. Examination of transition structures of previously performed allylations that proceeded with high ee revealed the importance of both local and global control elements in these successful reactions. The ability of density functional theory methods to estimate the enantioselectivity of these asymmetric ketone allylations was established. All allylations that were studied computationally exhibited low (<5 kcal/mol) activation barriers, a result that is consistent with the highly reactive nature of Nakamura’s reagent.

Graphical abstractAn investigation of the scope of enantioselective ketone allylations employing Nakamura’s chiral allylzinc–bisoxazoline reagent is described, along with the development of a theoretical model to explain the results.Figure optionsDownload full-size imageDownload as PowerPoint slide