Direct Catalytic Asymmetric Michael Addition Reaction Of Dialkyl Phosphites To 2-benzylidene-1-indanones By A Chiral Dinuclear Zinc Catalyst

Chiral organophosphorus compounds are attractive biologically active compounds and widely applied in agricultural,medicinal and synthetic chemistry.The catalytic enantioselective addition of phosphorus nucleophile is one of the most effective chemical transformation to obtain phosphonic acid derivatives.Different research groups have been focused on the asymmetric phospha-Michael addition of phosphorus nucleophile to nitroalkenes and ?,?-unsaturated carbonyl compounds in recent decades.In this thesis,we have studied the asymmetric 1,4-addition of dialkyl phosphites to 2-benzylidene-1-indanones catalyzed by a dinuclear zinc catalyst.We have optimized the experimental conditions such as solvents,additives,temperature and so on.In the presence of 20 mol% chiral ligand L3 and 40 mol% Et2 Zn,this reaction can afford corresponding product with excellent yield(up to 95%)and high enantioselectivitie(up to 99% ee,1/2.2 dr).With the opitmal reaction conditions achieved above,we subsequently examined the addition of diethyl phosphite to a range of 2-benzylidene-1-indanones to explore the generality of this reaction and most of them obtained moderate to excellent yields(83-99%)and high stereoselectivitie(up to 99% ee,7.3/1 dr).According to the experimental results,a possible mechanism was proposed to explain the origin of the asymmetric induction.