Mechanism Of Cu,Ir And Fe-catalyzed Boronization Of 1,3-dienes

Transition metal-catalyzed borocyanation and hydroboration reactions can effectively synthesize various homoallylic boronates,which has attracted extensive attention of organic chemists in recent years and is one of the most important and challenging fields of scientific research.In this paper,by virtue of the advantages of theoretical computational chemistry,we have studied and calculated in detail the activation mechanism of borocyanation and hydroboration catalyzed by transition metals Cu and Fe using density functional theory?DFT?and M06/B3LYP.In Chapter 3,the mechanism of regioselectivity in the Copper-Catalyzed Borocyanation of1,3-Dienes was studied.In this reaction,we elucidate the origins of ligand-and substrate-controlled regioselectivity.The mechanism rationalizes why ligand PCy₃favors1,2-borocupration while ligand Xant Phos favors 4,3-borocupration for 2-substituted 1,3-dienes,and why 1-substituted,1,2-disubstituted,and 1,3-disubstituted 1,3-dienes afford4,3-borocupration,irrespective of the presence of bidentate or monodentate ligands.Based on established experiments and stimulated by other relevant reactions,we attempted to enrich ligands and substrates computationally.The different regioselectivities for different substrates and ligands were attributed to different electronic and steric factors.In the fourth chapter,the mechanism of regioselectivity in the Fe-Catalyzed hydroboration of 1,3-Dienes.Because the regioselectivity of hydroboration remains challenging to control,the reaction mechanism and regioselectivity were calculated by DFT method and reveal the catalyst effects on regioselective control.the reaction of the catalyst proceeds via including oxidative addition to break the H–B?Bpin?bond.Hydrogen migration precedes boryl group migration.Then,iron which is coordinatively unsaturated,favors 4,1-insertion of the double bond of1,3-dienes to Fe–H bond and eventually generates 4,1-selectivity product.For 2-substituted 1,3-dienes,different substrates have different effect on double bond.Ligands were attributed to steric factors.The different bonding and coordination of metal leads to different regioselectivities.