Dedicated to the memory of Victor Snieckus, a pioneer of organometallic chemistry
and missing friend
Abstract
Cross-couplings involving organozinc reagents usually require a Pd-catalyst (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. Organozinc
compounds also undergo C–N bond formation with O-benzoylhydroxylamines or organic azides in the presence of cobalt- or iron-catalysts.
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
Key words
cross-coupling - organozinc reagents - carbon–carbon bond formation - carbon–nitrogen
bond formation - amination - diastereoselective reaction - enantioselective reaction
