# Chemodivergent Synthesis of 1,4-Benzo[b]dithiins and 1,4-Benzodithiafulvenes

## TL;DR

This paper describes a new method to make two types of sulfur-containing organic compounds using different solvents.

## Contribution

A chemodivergent synthesis method that produces different sulfur-based compounds based on solvent choice.

## Key findings

- Using DMF produces six-membered 1,4-dithiins.
- Using DMSO leads to ring contraction forming 1,4-dithiafulvenes.
- The solvent affects the S2–/S3• – equilibrium and base availability, controlling the product.

## Abstract

We report a chemodivergent synthesis of 1,4-benzo­[b]­dithiins and 1,4-benzodithiafulvenes from 2-iodoaryl alkynyl
sulfides
using a NaSH·xH2O/KOH system. In
DMF, the reaction affords six-membered 1,4-dithiins, whereas in DMSO,
these intermediates undergo a base-promoted ring contraction to the
corresponding 1,4-dithiafulvenes. Photophysical and mass spectrometry
studies support the idea that this chemodivergence arises from the
interplay between S2–/S3
• – equilibrium and base availability in
each solvent, which governs whether the 1,4-dithiin framework is preserved
or undergoes ring contraction to 1,4-benzodithiafulvenes.