in hexane Ar atmosphere, addn. of B-compound to soln. of PCl5 (during 40 min, 50°), stirring (2 h); solvent and POCl3 removal (14 Torr, <40°C), distn.;

in 1,3,5-trimethyl-benzene byproducts: CO; Ar atmosphere, heating (boiling); isomer mixt. (4-3''-η4/3'-4'η4 82:18) not separated, total yield 49percent; elem. anal.;

Multi-step reaction with 5 steps 1: tetrahydrofuran2: 1,3,5-trimethyl-benzene3: methyl iodide / tetrahydrofuran4: H2O / tetrahydrofuran5: diethyl ether