Highly Efficient Base Catalyzed N-alkylation of Amines with Alcohols and β-Alkylation of Secondary Alcohols with Primary Alcohols

Borrowing hydrogen (BH) reactions are very useful for the sustainable synthesis of C-C and C-N bonds. They generally operate with transition metal-based catalysts along with stoichiometric/catalytic amounts of added base. Here we report that two catalytic transformations, generally carried out with the BH methodology, i. e. N-alkylation of amines with alcohols and & beta;-alkylation of secondary alcohols with primary alcohols, can be performed very effectively with just catalytic amounts of base under air without using any transition metal-based catalyst. The mechanism is proposed to be based on air oxidation of the alcohol to aldehyde followed by condensation to an unsaturated intermediate which undergoes transfer hydrogenation with alcohol to the product.