Synthesis of P,P-bidentate caged phosphines via tungsten pentacarbonyl-promoted cycloaddition reactions of 1-alkyl-1,2-diphospholes

Abstract

Utilizing the W(CO)₅ group as a promoter, we have established a straightforward pathway for the conversion of simple 1-alkyl-1,2-diphospholes to P,P-bidentate caged phosphines via [4+2] cycloaddition reactions. Furthermore, during the course of our investigation, we have observed a rare instance of isomerization, wherein the W(CO)₅ migrates between the two phosphorus atoms in pentacarbonyl(1-alkyl-1,2-diphosphole)tungsten(0). This intriguing phenomenon has been thoroughly investigated using variable-temperature ³¹P NMR spectroscopy.