Abstract Aldehydes and methyl ketones readily afford 5, 6-dihydro-1, 4-dithiins that can be converted by n-butyllithium into their corresponding sulfur stabilized carbanions. Coupling of the latter with alkyl halides leads to species having a cis-configurated, disubstituted double bond tied up by the sulfur-containing ring which is known to be susceptible of selective removal.
