N‐Directed Pd‐Catalyzed Direct ortho‐Acetoxylation and ortho‐tert‐Butoxylation of 2‐Phenyl‐4H‐benzo[d][1,3]oxazin‐4‐ones via C‐H Activation

Abstract

A highly efficient, palladium‐catalyzed protocol for the regioselective ortho‐acyloxylation of 4H‐Benzo[d][1,3]oxazin‐4‐ones and various other heterocycles which includes indoline, 3,4‐dihydro‐2H‐benzo[b][1,4]oxazine, and 1‐methyl‐3‐phenylquinoxalin‐2(1H)‐one has been developed using C−H activation strategy. The protocol exploits the directing group property of nitrogen present in the heterocyclic framework to introduce the acyloxyl group onto heterocyclic compounds with excellent regioselectivity. The developed method offers a wide substrate and excellent functional group tolerance.

Ni‐Catalyzed/mediated C−X (X=N, O, S) Bond Formation Chelation‐Assisted by Bidentate Directing Groups

“…With the rapid development of methodology, how to rapidly construct the CÀ O bond was attracted more and more attention. In the past, the method of CÀ H functionalization reaction is largely limited to palladium, [84][85][86][87] copper, [88,89] cobalt [90][91][92] to construct CÀ O bond. Recently, lowpriced metal catalyzed CÀ H Acyloxylation [83] reactions have been attracted more attention, especially nickel salts as promising promoter during CÀ O bond forming process.…”

Rhodium-catalyzed selenylation and sulfenylation of quinoxalinones ‘on water’

“…However, till date, direct selenylation and sulfenylation of heterocyclic compounds have not been reported ‘on water’. Thus, in continuation of our efforts to develop the sustainable and greener protocols for the C–H functionalization of various biologically active heterocycles, 31 we herein are reporting the regioselective selenisation and sulfenylation of pharmaceutically important 3-phenyl quinoxalinones ( Fig. 2 ) using rhodium( iii ) catalyst ‘on water’.…”