Abstract: A process for preparing alkenes by reaction of various sulfone substrates with carbon tetrahalide in the presence of a strong base. The reactions are accelerated by the presence of a polar compound. Sulfone carbanions attack the carbon tetrahalide to produce an .alpha.-halogenated intermediate and a dihalocarbene. .alpha.-Halosulfones having .alpha.' hydrogens are converted to alkenes in situ via the Ramberg-Backland reaction. Sulfones having .alpha. but no .alpha.' hydrogens are simply .alpha.-halogenated. The dihalocarbene generated in the reaction may attack the product, solvent, or another substrate to form other products. Alkenes produced by reaction of carbon tetrahalides with di-sec-alkyl sulfones are readily attacked by dihalocarbene to form the alkene-dihalocarbene adduct (a substituted 1,1-dihalocyclopropane).