A Study On The Reactions Of Transition-Metal Catalyzed Organozinc Halides With Aromatic Aldehydes And Amines

Although organozinc reagent is one of the earliest prepared organometallics, The applications of organozinc reagent in organic synthesis have been limited for a long time. The reason is that it is inactive towards most of electrophiles except Reformatsky reagent. However, over the last few decades the use of transition metal catalysts, especially those containing Cu, Pd and Ni has converted otherwise unreactive or sluggishly reactive organozincs into higherly reactive reagents for the formation of Carbon-Carbon bonds.For the addition reaction of organozinc halides and Carbonyl compounds, some literature showed that CuCN/2LiCl was almost used as catalyst and the amount of CuCN/2LiCl used was stoichiometric. Because of toxity of CN-, we try to carry out the reaction in other way instead of CuCN/2LiCl. We attempted to use Pd(PPh3)2Cl2 as catalyst for the addition reaction of organozinc haldes and aromatic aldehydes and get better results; Diorganozinc has been studied in the electrophilic reaction of organozinc reagents and amine, The reactivity of organozinc halides is lower than diorganozincs . However, our experimental results showed Pd(PPh3)2Cl2 Can catalyzed effectively the electrophilic reaction of organozinc and aromatic amine. Furthermore this reaction also expends the application of organozincs in the organozinc synthesis.This thesis including four chapters:Chapter one: transition metal catalyzed reactions of organozinc reagentsIn this section, transition metal especially Cu, Pd and Ni catalyzed the reactions of organozinc reagents were reviewed in detail.Chapter two: Microwave assisted Nickel(II) catalyzed olefination of alkylzinc reagentswith aryl aldehydes.Microwave technology was applied in the reaction of Ni(II) catalyzed the olefination of alkylzinc and aromatic aldehydes in the present of Me3SiCl. The experimental results showed that this reaction proceeded effectively and rapidly under microwave irradiation. A reaction which proceeded in traditional method for more than 10 hours just needed a few minutes with a satisfactory yield under microwave irradiation. The main advantages of this method are rapidreaction speed, high stereoselectiveity, convenient operation and work-up.Chapter three: Pd(II)catalyzed the addition reaction of organozinc halides and aromatic aldehydesIn this section, we investigated mainly the 1,2-addition reaction of benzylzinc and allylzinc with aldehydes using PdCl2(PPh3)2 in the absent of Me3SiCl, and explored the reaction mechanism. The experimental results showed this reaction can proceed efficiently to produce second alcohol with higher yield, avoided the use of toxic CuCN/2LiCl, and simplified the operation and work-up of this addition reaction.Chapter four: Pd(II) catalyzed the electrophilic reaction of organozinc halide with aromatic amine.In this section, we firstly reported the electrophilic reaction of organozinc halide with aromatic amine catalyzed by catalytic amount PdCl2(PPh3)2. It was found from the experiments that this reaction can proceed smoothly in a mild condition (room temp.), naturally which provided a convenient pathway for N-alkylation of organozinc reagent and expended the applying scope of organozinc reagents in organic synthesis.