Activation of Remote meta‐C−H Bonds in Arenes with Tethered Alcohols: A Salicylonitrile Template

Abstract

Palladium-catalyzed activation of remote meta-C À H bonds in arenes containing tethered alcohols was achieved with high regioselectivity by using anitrile template.Computational studies on the macrocyclic transition state of the regioselectivity-determining CÀHactivation steps revealed that both the C-N-Ag angles and gauche comformations of phenyl ether play an extremely important role in the meta selectivity.

Diverse meta‐C−H Functionalization of Arenes across Different Linker Lengths

“…However,the formation of abimetallic Pd-Ag adduct with the substrate could facilitate the meta functionalization of longchain-containing scaffolds as proposed in recent reports. [8,10] Ad etailed mechanistic understanding remains as tudy of interest for our group.…”

“…In this context, striking ap roper balance between the number of atoms required for maintaining the core metallacyclic TS and directing the coordinating nitrile group to the target meta site has been identified to be crucial. [8] An increase in the number of atoms involved in the metallacycle raises the entropic barrier and offsets the situation of the catalyst at the optimum site for systems containing long chains.Furthermore,chemists have aimed for atemplate that would facilitate aplethora of functionalizations without any compromise in selectivity.…”

Diverse meta‐C−H Functionalization of Arenes across Different Linker Lengths

“…[8,10] Ad etailed mechanistic understanding remains as tudy of interest for our group. However,the formation of abimetallic Pd-Ag adduct with the substrate could facilitate the meta functionalization of longchain-containing scaffolds as proposed in recent reports.…”

“…[4,5] Functionalizations that are difficult to accomplish at the meta-position of arenes using nitrile coordination have been acheived by the judicious design of relatively stronger coordinating directing groups. [8] An increase in the number of atoms involved in the metallacycle raises the entropic barrier and offsets the situation of the catalyst at the optimum site for systems containing long chains.Furthermore,chemists have aimed for atemplate that would facilitate aplethora of functionalizations without any compromise in selectivity. In this context, striking ap roper balance between the number of atoms required for maintaining the core metallacyclic TS and directing the coordinating nitrile group to the target meta site has been identified to be crucial.…”

Arene C–H Iodination Using Aryl Iodides

“…Initially, we used the hydrocinnamic amide 1a' (Table 1) bearing an aryl carboxyl meta-directing template as the substrate to investigate the C-H iodination using an aryl iodide, since desired meta-C-H iodinated product had been obtained as a side product with 1a' in our previous study. 61 Moreover, meta-C-H iodination [70][71][72] of arenes is still very limited to narrow substrate scope, [90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105][106][107] and hydrocinnamic acids are a class of important core structure of biologically active molecules such as drug Baclofen.…”