Preparation of organozinc halides via transmetallations

The lithiation of an O-vinyl carbamate with rAr-BuLi followed by transmetallation with zinc bromide provides the convenient acyl anion derivative, which undergoes smooth Pd(0)-catalyzed cross-coupling reactions (Equation (24)).67 This reaction sequence has been extended to lithium enolates. The deprotonation of the aminoester with LDA followed by a transmetallation with zinc bromide in ether furnishes a zinc enolate, which readily adds to the double 

The hydroboration of allylic amine or alcohol derivatives can be used for the preparation of alkylzinc reagents with excellent diastereoselectivity (Equation (34)). Rhodium-catalyzed hydroborations are also compatible 

Transmetallations starting from alkenylzirconium species, which are obtained by hydrozirconation using H(Cl)ZrCp2, are readily accomplished.98,99 3 Ichikawa, Minami, and co-workers have elegantly shown that diflurovinylzinc iodide is obtained by the addition of ZrCp2 to the corresponding alkenyl tosylate (Equation (36)). In situ transmetallation reactions have also been reported. 

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