Mechanistic Insight in an Improved Allylboration of Ketones

Significance

The authors report a highly improved allylboration of ketones and mechanistic studies towards the kinetics of the transformation. The utilization of alcohols as an additive improved the reaction in terms of turnover and enantioselectivity. By this observation the final catalyst liberation (k ₄) is suggested to be the real rate-determining step and not the primary reversible ligand exchange (k ₁/k _-1), thus enabling a considerable decrease in catalyst loading (2 mol%). The utilization of tethered allylboranes further increased the performance of the reaction.