Phenyl 2- ethynyl sulfone

Phenyl 2-(trimethylsilyl)ethynyl sulfone (118) can act as a vinyl cation synthon (equations 93 and 94)78 79. Thus, the reaction of enolates with 118 and subsequent desulfonylation of the adduct gives a-vinyl ketone, such as 119 and 120. 

Phenyl 2-(trimethylsil>l)ethynyl sulfone, C6H5S02C=CSi(CH3)3 (1). Mol. wt. 238.38, m.p. 64-65°. Prepared by reaction of bis(trimethylsilyl)acetylene with C6H5S02C1-A1C13 in CH2C12 (65% yield).1... 

MICHAEL ADDITIONS Alumina. Aluminum chloride. Cesium fluoride-Silicon(lV) cthoxidc. 1,4-Diazabicyclo[2.2.2]octanc. l,8-Diazabicyclo[5.4.0]-7-undecene. Ketene r-butyldimethylsilyl methyl acetal. Lithium acetylides. (S)-( + )-2-Mcthoxymethylpyrrolidine. Methyl lithiodithioacetate. Methyl (phcnylsulfinyl)acetate. Methyl 2-trimcthylsilylacrylate. Nickel carbonyl. Organocopper reagents. 8-Phenylmcnthol. Phenyl 2-(trimethylsilyl)ethynyl sulfone. Tetra-n-butylammonium fluoride. Tiianium(IV) chloride. 3-Triisopropylsilylpropynyllithiuni. Zirconium(IV) n-propoxiilc... 

DIENOPHILES Acrolein. Ethynyl p-tolyl sulfone. 3-Methylsulfonyl-2,5-dihydro-furane. 3-Nitro-2-cyclohexenone. Phenyl vinyl sulfone. 

The influence of substituents in alkynes is also demonstrated by Padwa and Wannamaker (1990) for the reaction of 2-diazopropane with aryl-ethynyl sulfones (6.30), substituted in the 2-position with either a methyl, phenyl, or trimethylsilyl group. As shown in (6-21) addition of the aryl 2-(trimethylsilyl)ethynyl sulfone takes place with a specificity that is the reverse of that of the compounds containing a methyl or phenyl group in the 2-position. 

In an analogous reaction, bis-(pentafluorophenyl)-sulfone is used for the preparation of poly(arylene ether sulfone) (PAES). Bis-(pentafluorophenyl)-sulfone is prepared by the oxidation of bis-(pentafluorophenyl)-sulfide. In the next step, 3-ethynylphenol or 4-(phenyl-ethynyl)phenoI is attached to the PSI, or PAES [39]. These groups are capable of thermal crosslinking. Fluorinated PSI [6] or PAES [40] can be used for optical waveguide applications. 

Dienophiles, phenyl vinyl sulfone 59, and ethynyl sulfone 60 in Diels-Alder reactions can serve as potential ethene and ethyne equivalents, respectively. 

The procedures used most often for preparation of arylsulfonyl acetylenes Involve oxidation of the corresponding ethynyl thio ether. The thio ethers are usually obtained via a two-step sequence beginning with two-fold thiophenoxide displacement of chloride ion from cis-l,2-dichloroethylene, followed by elimination with n-butyl1ithium in the resultant cis-1,2-bisarylthioethylene. Less well known methods involve diazotization of 4-arylsulfonyl-5-aminoisoxazoles, dehydrobrpmination of cis- and trans-2-bromovinyl phenyl sulfone with fluoride ion, and oxidative elimination of - phenylseleno)vinyl sulfones. The method described here, which bypasses the need for strongly basic conditions, is adapted from the work of Bhattacharya, Josiah, and Walton. The simplicity and mildness of the method suggest that it may be broadly useful. 

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