Cross-Coupling of Mesylated Phenol Derivatives with Potassium Cyclopropyltrifluoroborate

Cyclopropylation of aromatic rings using mesylates as starting materials.

Another paper by Molander et al. (University of Pennsylvania, Penn., USA). As expected, a work using trifluoroborates. In this case, potassium cyclopropyltrifluoroborate, but not over the usual (hetero)aromatic halide or triflate. The substrates here are mesylates, which no long ago were not suitable partners for the Suzuki-Miyaura coupling. The paper includes 10 examples with common aromatic mesylates and 6 examples with heterocyclic mesylates. The usual yields are excellent, but it seems the reaction has some problems when electron withdrawing substituents are present.

J. Org. Chem., Article ASAP. See: 10.1021/jo2015246