1,3-Dithiolane

1,3-Dithiolane is the organosulfur compound with the formula CH2S2C2H4. Also classified as a heterocycle related cyclopentane by replacing two methylene bridges (-- units) with thioether groups. It is an isomer of 1,2-dithiolane. 1,3-Dithiolanes are compounds where one or more H atoms of the parent 1,3-dithiolane are replaced by other groups. These species are more widely studied.

Synthesis
A common family of 1,3-dithiolanes have the formula RCHS2C2H4. They are obtained by treating an aldehyde with 1,2-ethanedithiol. Related compounds with the formula R2CS2C2H4 are obtained by condensation of 1,2-ethanedithiol with ketones. The dithiolane protected aldehydes and ketones are amenable to many reactions without perturbing the dithiolane ring.

Dithiolanes can often be reverted, i.e., deprotected, to the parent aldehyde and ketone. A variety of reagents have been developed for that purpose.

Reactions
1,3-Dithiolanes derived from aldehydes can be deprotonated:
 * RCHS2C2H4 + BuLi  ->  RCLiS2C2H4  +  BuH

These organolithium compounds degrade with loss of ethylene to give the dthiocarboxylate:
 * RCLiS2C2H4 -> RCS2Li  +  C2H4

In contrast, 2-lithio-1,3-dithianes (RCLiS2C3H6) are long-lived.

1,3-Dithiolanes are susceptible to a variety of degradation processes involving organometallic reagents leading to other organosulfur compounds.