in tetrahydrofuran equimolar amts. of reactants are stirred under Ar in THF soln. for ca. 2 h; chromy. (silica gel, benzene); vol. of the soln. reduced, addn. of petroleum ether yields the solid product;

in hexadeuterioacetone Kinetics; 20°C; reaction followed by (1)H NMR spectroscopy;