Cobalt-and Iron-Catalyzed Acceptorless Dehydrogenative Coupling Reactions To ?-alkylated Ketones,Quinolines And Quinazolines

Alcohols,which can be derived from abundantly available biomass.are sustainable sources and used as coupling partners in organic synthesis.During the past decades,noble metal-catalyzed acceptorless dehydrogenative coupling(ADC)of alcohols has been attracted much attention.In the recent years.noble-metal-free catalysts,such as phosphine-ligated pincer Fe.Co.Ni,Mn complexes were reported to mediate these cross-coupling reactions.In this thesis,phosphine-free cobalt and ferric catalytic systems exhibited high catalytic activity and selectivity in the cross-coupling of secondary and primary alcohols to ?-alkylated ketones,dehydrogenative annulation of 2-aminobenzyl alcohols with secondary alcohols to quinolines,cross-couplings of secondary alcohols with 2-aminobenzyl alcohols to quinoline derivatives.Reactions of CpCl2 with a series of phosphine-free NH-NNN pincer ligands produce corresponding Co(II)-NNN complexes.Cobalt(?)complexes(5 mol%Co)efficiently catalyzes acceptorless dehydrogenative cross coupling of secondary and primary alcohols to selectively form a-alkylated ketones using NaOH(20 mol%)as a base in toluene at 120?.This catalytic system displayed wide applicability to a diverse range of substrates.The NH group on the Co(?)-NNN precatalyst controls the activity and selectivity.This simple catalytic system is involved in the synthesis of quinolines via the dehydrogenative annulation of 2-aminobenzyl alcohols with secondary alcohols.FeCl2·4H2O/phenanthroline efficiently catalyzes acceptorless dehydrogenation coupling reaction of(2-aminophenyl)methanols with benzamides to quinazolines with H2 and H2O as byproducts using CsOH(70 mol%)as a base in toluene at 130?.This coupling reaction tolerates a wide range of functional groups.This protocol is high atom-economic and environmentally benign.which does not require any additives.