Rhodium/Cobalt-catalyzed C?H Bond Activation For The Synthesis Of New C?C Bond

Transition-metal-catalyzed inert C-H bond functionalization has been identified as a powerful tool for alkylarene syntheses,which has received considerable recent attention.In this thesis,we have developed a series of alkylation and annulation reactions through rhodium-and cobalt-catalyzed aryl C-H activation strategy.See below for details:1.Carboxylate-enhanced rhodium(?)-catalyzed 1,4-addition with conjugated alkenes under mild conditionsA mild rhodium(?)-catalyzed C-H alkylation between(hetero)aryl oximes,pyri(mi)dine,as well as pyrazoles and?,?-unsaturated carbonyl compounds was developed.The versatile rhodium(?)catalysis featured excellent functional group tolerance,broad substrate scope and oxidant-free reaction conditions.2.Cobalt(?)-catalyzed C–H hydroarylation of conjugated C=C/C=O bondsHighly C-2-selective indole C–H hydroarylation of acrolein,enones,and glyoxylates was achieved.The versatile cobalt catalyst overcomes the inherent C-3 selectivity with the assistance of pyrimidinyl,pyridyl,and pyrazolyl directing groups.This approach provided an expedient route to indolyl-substituted aldehydes,ketones,and esters with wide functional group tolerance.In addition,it also features high step-and atom-economy.3.Cobalt(?)-catalyzed C(sp~2)-H alkylation with maleimides and maleate estersUnder mild reaction conditions,this cobalt(?)catalysis displayed excellent site-and chemo-selectivity,as well as broad substrate scope.Thus providing an expedient access to pharmacologically useful succinimides.4.Selective synthesis of isoquinolines by rhodium(?)-catalyzed C-H/N-H functionali-zation with??substituted ketonesA rhodium(?)-catalyzed C-H/N-H bond functionalization for the synthesis of C-3-mono-substituted 1-aminoisoquinolines from aryl amidines and?-MsO/TsO/Cl ketones was achieved without the use of oxidant.Moreover,a facile removal of the tertiary butyl group under exceedingly mild reaction conditions was illustrated,which provided a possibility for further modification.