Molecular Iodine Initiates Hydroborations of Alkenes with N-Heterocyclic Carbene Boranes

Xiangcheng Pan (1) , Anne Boussonniere (2, 1) , Dennis Curran (1)

1 Department of Chemistry (University of Pittsburgh)
2 IMMM - Institut des Molécules et Matériaux du Mans

The hydroboration of alkenes of diverse structural types by assorted N-heterocyclic carbene boranes can be accomplished by addition of 5-10% diiodine. For example, reaction of 1,3-dimethylimidazol-2-ylidene borane (diMe-Imd-BH3) with 10% I-2 followed by addition of 2,3-dimethyl-2-butene provided the corresponding thexyl NHC-borane (diMe-Imd-BH(2)thexyl) in 75% yield. This and related monohydroboration products are stable to chromatography and storage. The scope of the new reaction is described, and the mechanism is probed by B-11 NMR experiments.

Domaines: Chimie organique

Xiangcheng Pan, Anne Boussonniere, Dennis Curran. Molecular Iodine Initiates Hydroborations of Alkenes with N-Heterocyclic Carbene Boranes. Journal of the American Chemical Society, 2013, 135 (38), pp.14433-14437. ⟨10.1021/ja407678e⟩. ⟨hal-02163308⟩