Abstract Low-pressure thermal generation of a range of o-alkylthiophenylcarbenes produces, in addition to the normal insertion products, styrenes and 1, 3-dihydrobenzo [c] thiophens-clearly arising from rearrangement. The main features of their mechanism of formation are established by deuterium-labelling studies: in both cases participation by S- ylids is implicated.
![1,3-dihydro-1-methylbenzo[c]thiophen Structure](https://image.chemsrc.com/caspic/023/94636-81-4.png)