Head-to-head polymers — XXXII: Toward head-to-head poly(α-methylstyrene): Synthesis of 2,3-dimethyl-2,3-diphenylbutanediol-1,4-ditosylate and 1,4-diphenyl-2,3-dimethylbutadiene-1,3

2,3-Dimethyl-2,3-diphenylbutanediol-1,4-ditosylate (7) was synthesized starting from 2-phenylpropionic acid (1). The acid chloride was brominated and transformed into methyl 2-phenyl-2-bromo-propionate (4) which was coupled with a zinc/copper couple to dimethyl 2,3-dimethyl-2,3-diphenylsuccinate (5). Reduction with lithium aluminum hydride to 2,3-dimethyl-2,3-diphenylbutanediol-1,4 (6) was followed by tosylation. The tosylate 7 a mixture of the meso and racemic compounds, could be separated into the pure isomers,a m. p. 170 °C andb m. p. 121 °C. The mixture of each individual pure compound, when treated with tetraalkyl-ammonium bromide, did not give the expected 2,3-dimethyl-2,3-diphenyl-1,4-dibromobutane (9) but rather 1,4-diphenyl-2,3-dimethylbutadiene-1,3 (8). The identity of the compound was established by independent unequivocal synthesis, the comparison of spectral characteristics, and mixed melting point.