Palladium-catalyzed synthesis of 4-cyclohexylmorpholines from reductive coupling of aryl ethers and lignin model compounds with morpholines?

Green Chemistry Pub Date: 2020-11-17 DOI: 10.1039/D0GC03188G

Abstract

This work describes the highly efficient Pd-catalyzed direct coupling of aryl ethers (including the typical lignin model compounds) and morpholines to produce 4-cyclohexylmorpholines, a useful class of fine chemicals. Without employing any acidic additives, various 4-cyclohexylmorpholines could be synthesized with good yields from a variety of aryl ethers using H2 as a hydrogen resource. A mechanism study revealed that the desired product was formed via the cleavage of the C(Ar)–O bonds to generate the corresponding cyclohexanones and subsequent reductive amination.

Graphical abstract: Palladium-catalyzed synthesis of 4-cyclohexylmorpholines from reductive coupling of aryl ethers and lignin model compounds with morpholines
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