1,3-Dithiolane is the organosulfur compound with the formula CH₂S₂C₂H₄. Also classified as a heterocycle related cyclopentane by replacing two methylene bridges (-CH
₂- units) with thioether groups. It is an isomer of 1,2-dithiolane.^[1]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.

A common family of 1,3-dithiolanes have the formula RCHS₂C₂H₄. They are obtained by treating an aldehyde with 1,2-ethanedithiol.^[2] Related compounds with the formula R₂CS₂C₂H₄ are obtained by condensation of 1,2-ethanedithiol with ketones.^[3] The dithiolane protected aldehydes and ketones are amenable to many reactions without perturbing the dithiolane ring.^[4]

Dithiolanes can often be reverted, i.e., deprotected,^[5] to the parent aldehyde and ketone. A variety of reagents have been developed for that purpose.^[6]

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.^[2][3]