Benzylzinc halides

Reactions of allyl- and benzylzinc halides with polymer-supported imines 398... 

During the past decade, the main focus of studies related to the well-known349 CeCl3- or SnCl2-catalyzed reactions of allylzinc and benzylzinc halides with imines was the application of polymer-supported chiral imines.350,351 An example of such reactions is shown in Scheme 135.350 It should be noted that attempts using arylzinc reagents in... 

Benzyl(trifluoroacetato) complexes, with platinum(II), 8, 470 Benzylzinc halides, with polymer-supported imines, 2, 398 Benzynes... 

To increase functional group compatibility a silver-catalyzed coupling of tertiary alkyl halides 324 with benzylzinc halides 325 (R4=Bn, M=Zn) was... 

Unsymmetrical biaryh and diarylmethanes. Negishi et al have used a nickel-(0) complex or a palladium(0) complex as catalyst for the cross-coupling of aryl-or benzylzinc halides with aryl halides at room temperature to form biaryls or diarylmethanes. The zinc derivatives are prepared by reaction of aryl- or benzyl-lithium with zinc chloride or bromide. 

In 1977 Kosugi et reported the Pd-catalyzed aUylation with aUyltins, which most probably is the first Pd-catalyzed aUylation reaction and the first Pd-catalyzed crosscoupling with organotins, whUe Negishi et al. reported what appears to be the first Pd-catalyzed benzylation with benzylzinc halides. So, Pd-catalyzed aUylation and benzyla-tion began in 1977 (Scheme 1). The related propargylation most probably was reported first in 1980. Prior to these developments, the stoichiometric reaction of arylmercuric halides with allyl halides and Pd complexes was reported by Heck. The catalytic version of this and related reactions was later developed as tiie Heck reaction, as discussed in Part IV. 

Hinkle, R. J., Leri, A. C., David, G. A. and Erwin, W. M. 2000. Addition of benzylzinc halides to aUcenyl(phenyl)iodonium triflates Stereoselective synthesis of trisubstituted alkenes. Org. Lett 2 1521-1523. 

Scheme 4.29 Cu-catalyzed cross-coupling of benzylzinc halides with benzyl bromides [112, 113],...

Cunico and Pandey reported the palladium-catalyzed preparation of a-aryl tertiary amides using benzylic halides and carbamoylsilane [87], and, in this report, a disadvantage of using aminocarbonylation of benzyl halides was also described [90]. Accordingly, to expand the scope of this chemistry, we next focused on the use of benzylic organometallic reagents to develop a facile route for the synthesis of a-aryl tertiary amides. Since the appropriate benzylzinc halides were easily prepared via the direct insertion of highly active zinc, they were employed in the... 

As we expected, benzylzinc halides were readily coupled with carbamoyl chlorides to give rise to the desired amides in moderate yields. Coupling... 

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