Synthesis of biaryl imino/keto carboxylic acids via aryl amide directed C–H activation reaction

Abstract

A novel Pd-catalysed C-H activation reaction for the synthesis of biaryl imino/keto carboxylic acids is developed. This reaction underwent aryl amide directed C-H activation ortho-acylation followed by ring closing and ring opening processes to give a range of biaryl imino/keto carboxylic acids. Our methodology features the utilization of a cheap and green oxidant (TBHP) as well as readily available aldehydes.

Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

“…37 Oxidative C–H couplings with aromatic aldehydes were highly efficient, however, alkyl aldehydes were ineffective in the transformation.…”

Acylation of (Hetero)Arenes through CH Activation with Aroyl Surrogates

“…With N ‐substituted benzamides and aldehydes as the substrates, the desired hydroxyisoindolones were isolated in good yields (Scheme ). Interestingly, imino carboxylic acids can be prepared from the same substrates by simply adding the Lewis acid BF 3 ⋅ Et 2 O (Scheme ) 20b…”

Pd(II)‐Catalyzed Chelation‐Induced C(sp2)‐H Acylation of (Hetero)Arenes Using Toluenes as Aroyl Surrogate

“…From the Literature studies it is revealed that several oxidants such as air, [19a] Ag 2 CO 3 , [19b] PhI(OCOCF 3 ) 2 , [19c] (NH 4 ) 2 S 2 O 8 , [19d] K 2 S 2 O 8 , [19e,f] 3,3′,5,5′‐tetra‐ tert ‐butyldiphenoquinone (DPQ), [19g] peroxides [19h–k] i.e. Di‐ t ‐butyl peroxide (DTBP), dicumyl peroxide (DCP), (PhCOO) 2 , PhC(CH 3 ) 2 OOH, TBHP [ t ‐butyl hydroperoxide] and molecular oxygen (O 2 ) [19l] have been utilized for transition‐metal‐catalyzed oxidative coupling reaction with various acylating agents such as: aldehydes, α‐oxoacids, alcohols, arylmethyl amines, 1,2‐Diketone etc.…”