1,2-Additions of Organomagnesium Halides to Phosphaalkynes: Synthesis of 2-Phospha-1-vinylmagnesium Halides and a Novel Type of Magnesium-Phosphorus Cage Compound

Abstract

Grignard reagents such as isopropyl- and tert-butylmagnesium halide (2a: X = Cl; 2b: X = Br) react with tert-butylphosphaacetylene (1) in a regio- and stereoselective 1,2-addition process at −78 °C to give the 2-phospha-1-vinylmagnesium halides 3a,b in high yields. At elevated temperatures, the phosphavinylmagnesium chloride 3a reacts with two more equivalents of 1 to afford the previously unknown magnesium-phosphorus cage compound 4, the structure of which has been confirmed by X-ray-analysis.