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
Key words
zinc - palladium - allylzinc halides - Negishi cross-coupling
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.
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.
