One‐Pot Catalytic Conversion of Lignin‐Derivable Guaiacols and Syringols to Cyclohexylamines

Cyclic primary amines are elementary building blocks to many fine chemicals, pharmaceuticals, and polymers. Here, a powerful one‐pot Raney Ni‐based catalytic strategy was developed to transform guaiacol into cyclohexylamine using NH(3) (7 bar) and H(2) (10 bar) in up to 94 % yield. The methodology was extendable to the conversion of a wider range of guaiacols and syringols into their corresponding cyclohexylamines. Notably, a crude bio‐oil originating from the reductive catalytic fractionation of birch lignocellulose was transformed into a product mixture rich in 4‐propylcyclohexylamine, constituting an interesting case of catalytic funneling. The isolated yield of the desired 4‐propylcyclohexylamine reached as high as 7 wt % (on lignin basis). Preliminary mechanistic studies pointed at the consecutive occurrence of three key catalytic transformations, namely, demethoxylation, hydrogenation, and amination.