Solvent-free mechanochemical preparation of phosphonium salts, phosphorus ylides, and olefins

摘要

The present invention provides a method of preparing a phosphonium salt of the formula [R¹R²R³P—CR⁴R⁵R⁶]X, comprising ball-milling a phosphine of the formula R¹R²R³P with a compound of the formula XCR⁴R⁵R⁶; a method of preparing a phosphorus ylide of the formula R¹R²R³P═CR⁴R⁵, comprising ball-milling a phosphonium salt of the formula [R¹R²R³P—HCR⁴R⁵]X in the presence of a base; and a method of preparing an olefin of the formula R⁴R⁵C═CR⁷H or R⁴R⁵C═CR⁷R⁸, comprising ball-milling a phosphorus ylide of the formula R¹R²R³P═CR⁴R⁵ with a compound of the formula R⁷C(O)H or R⁷C(O)R⁸. The inventive method produces phosphonium salts and phosphorus ylides by mechanical processing solid reagents under solvent-free conditions. The advantages of the present invention over conventional solution methods, include: (1) extremely high selectivity; (2) high yields; (3) low processing temperatures; (4) simple and scalable reactions using commercially available equipment; and (5) the complete elimination of solvents from the reaction.