Cross-couplings involving organozinc reagents require usually a Pd-catalysis (Negishi cross-coupling), however, uncatalyzed cross-couplings of zinc organometallics proceed well in the absence of transition-metal catalysts with reactive electrophiles such as benzal 1,1-diacetates, benzhydryl acetates, and iminium trifluoroacetates. Also, organozinc compounds undergo C-N bond formations with O-benzoylhydroxylamines or organic azides in the presence of cobalt- or iron-catalysts. Besides, highly diastereoselective and enantioselective cross-couplings can be readily performed with room-temperature configurationally stable alkylzinc species producing diastereoselectively and enantiomerically enriched products. Finally, highly regioselective magnesiations of functionalized arenes and heteroarenes undergo Negishi (after transmetalation with ZnCl2) or Cu-catalyzed cross-couplings.
1 Introduction
2 Uncatalyzed Cross-Couplings of Organozinc Reagents with Highly Electrophilic Partners
3 Iron- and Cobalt-catalyzed Aminations Using Organozinc Reagents
4 Stereo- and Regioselective Cross-couplings of Organozinc Reagents
5 Conclusion
Synthesis of gaseous hydrocarbons from carbon monoxide and hydrogen over transition metal catalysts. 2. The activity and selectivity of graphite-supported iron catalysts.
