Preparation and Reactions of Highly Functionalized Bis-Arylzinc Reagents Using a Li(acac)-Catalyzed Iodine-Zinc Exchange

Abstract

Polyfunctional bis-arylzinc reagents are accessible via a new lithium acetylacetonate-catalyzed iodine-zinc exchange. This protocol tolerates sensitive functional groups (ketones, aldehydes or isothiocyanates) in the aryl iodides and allows the formation of highly functionalized zinc reagents. These zinc reagents can be used in a variety of catalyzed and uncatalyzed transformations.

Key words

functionalized zinc reagents - halogen-metal exchange - cross-coupling - nucleophilic catalysis

References

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18

The exact determination of all the concentrations of the solutions used (s-BuLi, ZnCl₂, s-Bu₂Zn) is decisive for the success of this procedure. Threefold titration and averaging have been typically done.

19

The complete absence of LiCl is decisive for the success of the iodine-zinc exchange procedure.

20

Threefold titration has been performed.

21

Prepared by acylation of 4-hydroxy-3,5-diiodobenzoate with Ac₂O (1.3 equiv) in pyridine in the presence of DMAP (0.1 equiv).