Hydrobismuthation: Insertion of Unsaturated Hydrocarbons into the Heaviest Main Group Element Bond to Hydrogen.

The bismuth hydride (2,6-Mes 2 H 3 C 6 ) 2 BiH ( 1 , Mes = 2,4,6-trimethylphenyl), which has a Bi-H 1 H NMR spectroscopic signal at δ = 19.64 ppm, was reacted with phenylacetylene at 60 °C in toluene to yield [(2,6-Mes 2 C 6 H 3 ) 2 BiC(Ph)=CH 2 ] ( 2 ) after 15 min. Compound 2 was characterized by 1 H, 13 C NMR, and UV-vis spectroscopy, single crystal X-ray crystallography, and calculations employing density functional theory. Compound 2 is the first example of a hydrobismuthation addition product and displays Markovnikov regioselectivity. Computational methods indicated that it forms via a radical mechanism with an associated Gibbs energy of activation of 91 kJ mol -1 and a reaction energy of -90 kJ mol -1 .