Stereoselective Thermal Addition of R_P and/or S_P-Menthyl-Deriving Secondary Phosphine Oxides to Active Alkynes, the Mechanism, Stereochemistry and Generation of P,C-Chirogenic Bis-Phosphine Derivatives

The additions of R-P-1 or S-P-1 to alkynyl esters stereo selectively afforded bis-phosphinylated derivatives having up to four C- and P-chirogenic centers. The stereochemistry was controlled by kinetic and thermodynamic processes at lower and higher temperature, respectively. At 100 degrees C, the bis-adducts were obtained in up to 99% yield and >99 : 1 d.r.