Expedient iron-catalyzed coupling of alkyl, benzyl and allyl halides with arylboronic esters.
While attractive, the iron-catalyzed coupling of arylboron reagents with alkyl halides typically requires expensive or synthetically challenging diphosphine ligands. Herein, we show that primary and secondary alkyl bromides and chlorides, as well as benzyl and allyl halides, can be coupled with arylboronic esters, activated with alkyllithium reagents, by using very simple iron-based catalysts. The catalysts used were either adducts of inexpensive and widely available diphosphines or, in a large number of cases, simply [Fe(acac)3] with no added co-ligands. In the former case, preliminary mechanistic studies highlight the likely involvement of iron(I)-phosphine intermediates.
School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK). r.bedford@bristol.ac.uk.
Robin B
RB
Bedford
Peter B
PB
Brenner
Emma
E
Carter
Thomas W
TW
Carvell
Paul M
PM
Cogswell
Timothy
T
Gallagher
Jeremy N
JN
Harvey
Damien M
DM
Murphy
Emily C
EC
Neeve
Joshua
J
Nunn
Dominic R
DR
Pye
Suzuki coupling; alkyl halides; catalysis; cross-coupling; iron