The Cover Feature represents two different roads available to carry out the N-alkylation of amines with alcohols. The first road is wide and taken by many people; it consists of transition metal catalysis operating via the well-known “borrowing-hydrogen” pathway. In contrast, the findings reported by M. T. Johnson, O. F. Wendt and co-workers in their Research Article lays out a road less travelled, using the presence of air along with catalytic amount of base to reach the final goal. As indicated by the magnification, the methodology has a broader scope than shown and can be applied to similar reactions, one example in the report being the β-alkylation of secondary alcohols with primary alcohols. More information can be found in the Research Article by M. T. Johnson, O. F. Wendt and co-workers.

Here we report that two very important catalytic transformations i. e., N-alkylation of amines with alcohols and β-alkylation of secondary alcohols with primary alcohols that is generally carried out with transition metal-based catalysts can be performed with a catalytic amount of base under air in a closed vessel without using transition metals or any other additives generating only water as byproduct.

Abstract

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 β-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.