Efficient cross-coupling of secondary alkyltrifluoroborates with aryl chlorides--reaction discovery using parallel microscale experimentation.
Microscale parallel experimentation was used to discover three catalyst systems capable of coupling secondary organotrifluoroborates with sterically and electronically demanding aryl chlorides and bromides. The ensuing results represent the first comprehensive study of alkylboron coupling to aryl chlorides and, in particular, using secondary alkylboron partners. A ligand-dependent beta-hydride elimination/reinsertion mechanism was implicated in the cross-coupling of more hindered substrates, leading to isomeric mixtures of coupled products in some cases.
Dreher
Spencer D
SD
Department of Process Research and the Catalytic Reactions Discovery and Development Laboratory, Merck and Co. Inc., 126 East Lincoln Avenue, Rahway, New Jersey 07065, USA. spencer_dreher@merck.com
Dormer
Peter G
PG
Sandrock
Deidre L
DL
Molander
Gary A
GA
D001555:Benzene Derivatives / Q000138:chemical synthesis* / Q000737:chemistry; D001881:Borates / Q000737:chemistry*; D002384:Catalysis; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry
D001555:Benzene Derivatives; D001881:Borates; D006842:Hydrocarbons, Brominated; D006843:Hydrocarbons, Chlorinated; D011725:Pyridines