Abstract
Treatment of diphenylacetylene with dimethylsulfinyl carbanion in dimethyl sulfoxide at room temperature gave two stereoisomeric compounds : trans-3-methylsulfinyl-1, 2-diphenyl-1-propene (I-a) and cis-3-methylsulfinyl-1, 2-diphenyl-1-propene (I-b) at a ratio of 88.5% and 11.5% respectively, which were confirmed by ultraviolet, infrared, nuclear magnetic resonance spectra and elemental analyses. Analogously trans-1-methylsulfinyl-2, 5-diphenyl-2-penten-4-yne (III-a) and cis-1-methylsulfinyl-3, 1-diphenyl-2-pentin-4-yne (III-b) at a ratio of 84% and 16% respectively, were obtained from 1, 4-diphenyl-1, 3-butadiyne and the carbanion. Treatment of the trans-sulfoxide (III-a) with the carbanion at room temperature gave a cis-trans mixture at a ratio of 84% of trans and 16% of cis isomer. Furthermore, 2, 3-diphenyl-1, 3-butadiene (II) was given from diphenylacetylene and methylsulfinyl carbanion at relatively high temperature.The proposed reaction mechanism affording II would probably involve double addition of the anion to triple bond followed by elimination of two moles of methanesulfinic acid.
