Synfacts 2014; 10(3): 0297
DOI: 10.1055/s-0033-1340750
Metal-Mediated Synthesis
© Georg Thieme Verlag Stuttgart · New York

Palladium-Catalyzed Linear-Selective Negishi Cross-Coupling of Allylzinc Halides

Contributor(s):
Paul Knochel
,
Nadja M. Barl
Yang Y, Mustard TJ. L, Cheong PH.-Y, * Buchwald SL. * Massachusetts Institute of Technology, Cambridge and Oregon State University, Corvallis, USA
Palladium-Catalyzed Completely Linear-Selective Negishi Cross-Coupling of Allylzinc Halides with Aryl and Vinyl Electrophiles.

Angew. Chem. Int. Ed. 2013;
52: 14098-14102
Further Information

Publication History

Publication Date:
17 February 2014 (online)

 

Significance

Cheong, Buchwald, and co-workers report the first completely linear-selective ­palladium-catalyzed Negishi cross-coupling of various 3,3-disubstituted allylzinc reagents with (hetero)aryl and vinyl (pseudo)halides, leading to prenylated (hetero)aryl and alkenyl compounds in high yield and with excellent regioselectivity.


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Comment

Apart from (hetero)aryl and vinyl bromides and chlorides, nonaflates and triflates were successfully used in this protocol. Computational studies reveal that an η1-α reductive elimination is preferred due to energetic reasons, leading exclusively to the prenylated products. Thus, the choice of catalyst and transmetalation reagent is crucial.


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