Benzylamine as an arylcarboxy surrogate: a copper catalysed o-benzoxylation of 2-phenylpyridines using benzyl amines

Abstract

Different reactivities and selectivities of Cu and Pd catalysts have been demonstrated in the reactions of benzylamines with 2-phenylpyridines.

Transition‐Metal‐Catalyzed Acyloxylation: Activation of C(sp2)–H and C(sp3)–H Bonds

“…Through the employment of acyl chlorides in the presence of O 2 as a clean oxidant, 20 mol‐% Cu(OAc) 2 and t BuOK, the acyloxy group was transferred to the product from carboxylic anhydrides, formed in situ from acyl chloride in the presence of base and moisture . Alternative surrogates for introducing arylcarboxy groups are: carboxylic acid sodium salts, alkynes and alkenes, aldehydes and methyl arenes, benzyl alcohols and benzylamines . The common point of the above substrates is their ability to form aldehydes, which undergo further oxidation to tert ‐butyl benzoperoxates, to install ArCOO – groups through the action of copper salts.…”

Recent Progress on Copper-Mediated Directing-Group-Assisted C(sp2)–H Activation

“…Later on, the same group (Scheme 17) 20 and that of Bhanage (Scheme 18 and Scheme 19) 21 independently reported similar reactions using benzylamine and benzyl alcohol as the benzoxylation sources.…”

The Rich Legacy and Bright Future of Transition‐Metal Catalyzed Peroxide Based Radical Reactions

“…This method has many advantages such as broad substrate scope, the use of inexpensive Cu II catalyst, and easily available starting materials (Scheme 17). [22] …”

“…This method has many advantages such as broad substrate scope, the use of inexpensive Cu II catalyst, and easily available starting materials (Scheme 17). [22] Initially, benzylamine is oxidized to imine (A) which on hydrolysis gives benzaldehyde (B). In the presence of an excess of TBHP, (B) or (B') is transformed to tert-butyl benzoperoxate (C).…”

“…The present methodology worked for a wide range of ligand directed substrates viz., 2-arylbezthiazoles, 2phenylpyridines, 2,3-diphenylquinoxaline, benzoquinoline, 2aroyloxypyridine, acetophenone O-methyl oxime etc. and afforded their o-aroylation products (22) in modest to good yields. Another notable feature is the good tolerance of functional groups (Scheme 21).…”