Ketone α-alkylation at the more-hindered site.Control of the regioselectivity of α-alkylation of carbonyl compounds is a longstanding topic of research in organic chemistry. 
Ketone α-alkylation at the more-hindered site
By using stoichiometric bulky strong bases and carefully adjusting the reaction conditions, selective alkylation of unsymmetrical ketones at less-hindered α-sites has been achieved. 
stoichiometric bulky strong bases
Here we report a nickel-catalysed alkylation of unsymmetrical ketones at the more-hindered α-sites with allylic alcohols. 
nickel-catalysed alkylation
Our results indicate that the space-constrained nickel catalyst bearing a bulky biphenyl diphosphine ligand enables the preferential alkylation of the more-substituted enolate over the less-substituted enolate and reverses the conventional regioselectivity of ketone α-alkylation. 
biphenyl diphosphine ligand