1,1-Carboboration of 1-Alkynes

Significance

The 1,1-carboboration of metallated alkynes has been known for some time (see Reviews below) and has been used for the synthesis of metalloles. The transformation is proposed to proceed through a zwitterionic intermediate, which triggers migration of an organic fragment from boron to carbon (see above). The authors have recently reported the 1,1-carboboration ­reaction of internal alkynes by way of a C-C ­activation event (C. Chen, G. Kehr, R. Fröhlich, G. Erker J. Am. Chem. Soc. 2010, 132, 13594). In the present report the authors demonstrate the 1,1-carboboration of 1-alkynes with strongly electrophilic boron reagents and demonstrate their Suzuki-Miyaura cross-coupling.

Reviews: B. Wrackmeyer Coord. Chem. Rev. 1995, 145, 125-156; B. Wrackmeyer Heteroat. Chem. 2006, 17, 188-208.