Dihydroboration of 1-alkynylphosphonates with 9-borabicyclo[3.3.1]nonane (9-BBN) followed by oxidation

ORGN 132

Narayan G. Bhat, nbhat@panam.edu, Department of Chemistry, University of Texas-Pan American, 1201 West University Drive, Edinburg, TX 78541 and Venessa D. Garate, Chemistry, University of Texas-Pan American, 1201 West University Drive, Edinburg, TX 78541.
1-Alkynylphosphonates easily prepared by the deprotonation of the terminal alkynes with n-butyllithium followed by reaction with diethylchlorophosphonates, readily undergo dihydroboration with 9-borabicyclo[3.3.1]nonane (9-BBN) in tetrahydrofuran at room temperature for 12 hours. The resulting dihydroborated products are reacted with alkaline hydrogen peroxide at 0 oC followed by stirring at room temperature for 4 hours to provide the corresponding 1-alkanols containing alpha-phosphonate moiety in excellent yields (72%-84%). The structures of these hydroxyphosphonates are confirmed by PMR and CMR spectral data.