Novel route to (Z)-1-alkenylboronate esters

ORGN 545

Narayan G. Bhat, nbhat@panam.edu, Department of Chemistry, University of Texas-Pan American, 1201 West University Drive, Edinburg, TX 78541 and Faustino Gutierrez, Chemistry, University of Texas-Pan American, 1201 West University Drive, Edinburg, TX 78541.
(Z)-1-Trimethylgermyl-1-alkenes easily prepared by the hydrozirconation of the corresponding 1-trimethylgermyl-1-alkynes followed by hydrolysis readily react with boron trichloride in hexanes for 4 h at room temperature. They resulting boron intermediates are then treated with water at 0 oC followed by extraction with ether. The resulting (Z)-1-alkenylboronic acids are then esterified with 1,3-propane diol in n-pentane for 1 h at room temperature. (Z)-1-Alkenylboronate esters are then isolated in good yieids (74%-88%) and their structures are confirmed by spectral (PMR and CMR) data.