Reactions of (1-nitroethenyl)sulfonylbenzene, a nitroethene derivative geminally substituted by a second W-group

Nitroaldol reaction of phenylsulfonylnitromethane with formaldehyde affords a mixture of 2,4-dinitro-2,4-bis(phenylsulfonyl)butan-l-ol and 2,4-dinitro-2,4-bis(phenylsufonyl)pentane-1,5-diol. Treatment of this mixture with base followed by reacidification affords 1,1'-[(1,3-dinitro-1,3-propanediyl)bis(sulfonyl)]bis(benzene) as a mixture of (R*, R*) and (R*, S*)-diastereomers from which the (R*, S*)-diastereomer can be obtained pure. The intermediate in the nitroaldol reaction is (1 -nitroethenyl)sulfonylbenzene and, if clienes are present, additional products are also obtained. If either (E)-2-methyl-1,3-pentadiene or 1-(1-methylethenyl)cyclohexene are present, typical Diels-Aider adducts are obtained with the major isomers explainable by assuming a transition state in which the nitro group is endo. if furan is present, its formal conjugate addition product, 2-[2-nitro-2-(phenylsulfanyl)ethyl]furan, is formed. If cyclooctatetraene is present, it first dimerizes and then affords isomeric Diels-Alder cycloadducts of the dimer. Semiempirical calculations comparing the LUMO energies of (1-nitroethenyl)sulfonylbenzene to the corresponding trans-1,2 isomer are presented to explain relative reactivity of 1,1- and 1,2-disubstituted dienophiles. Copyright (C) 2009 John Wiley & Sons, Ltd.