in diethyl ether N2 atmosphere; addn. of soln. of MeMgBr in Et2O to soln. of B-compd. in Et2O(room temp.), stirring (1 h, room temp.), addn. of p-vinylmagnesiumbromide, stirring (overnight, room temp.); filtn., removal of solvent, extn. (hexane), filtn., removal of solvent, recrystn. (hexane); elem. anal.;

diethyl ether

byproducts: N2;