Exchange halogen-zinc

The presence of a remote C=C double bond in the alkyl halide was critical saturated analogs underwent nickel-catalyzed halogen-zinc exchange.248 It has been suggested that the double bond coordinates to the nickel atom. As a 7r-acceptor, the C=C bond removes some electron density from the metal, thus facilitating the reductive coupling (Scheme 154).246... 

The cross-coupling of alkynylzinc halides or fluorinated alkenylzinc halides with fluori-nated alkenyl iodides allows the preparation of a range of fluorinated dienes or enynes - Functionalized allylic boronic esters can be prepared by the cross-coupling of (dialkylbo-ryl)methylzinc iodide 428 with functionalized alkenyl iodides. The intramolecular reaction provides cyclized products, such as 429 (Scheme 109) ° °. In some cases, reduction reactions or halogen-zinc exchange reactions are observed. 

C. Preparation of Mixed Zincates by Halogen-Zinc Exchange Reaction. . . 688... 

Table 5.10 Halogen-zinc exchange reaction in the presence of P4...

Ueno, M., Wheatley, A.E.H. and Kondo, Y. (2006) Phosphazene base-promoted halogen-zinc exchange reaction of aryl iodides using diethylzinc. Chemical Communications, 3549-3550. 

Aminoheteroaryl chlorides can also be coupled in good yields with dialkylzincs or alkylzinc chlorides in dioxane at 65 °C in the presence of NiCl2(dppp). In addition, as this nickel complex also catalyzes the halogen-zinc exchange, generation of alkylzincs from alkyl bromides and diethylzinc can be achieved in situ (Scheme 4.90) [283]. 

Halogen-Zinc Exchange of Lithium Zincate and Subsequent Trapping Reactions ... 

Table 16 Halogen-zinc exchange and catalyst-transfer polycondensation for synthesis of regioregular P3HT using zincate...

Kondo Y, Takazawa N, Yamazaki C, Sakamoto T (1994) Halogen-zinc exchange reaction of haloaromatics with lithium trimethylzincate. J Org Chem 59 4717-4718. doi 10.1021/ Jo00096a005... 

Nakamura 8, Liu C-Y, Muranaka A, Uchiyama M (2009) Theoretical study on the halogen-zinc exchange reaction by using organozincate compounds. Chem Eur J 15 5686-5694. doi 10.1002/chem.200802393... 

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