A one-pot synthesis of strained heterobicycles such as 2-thia (or 2-aza)-3-iminobicyclo [2.2. 0] hex-5-enes and 2-thia-3-azabicyclo [4.2. 0]~ 7-ene 2-oxides from alkynes, aluminum halides, and heterocumulenes (isothiocyanates, carbodiimides, N-sulfinylaniline) is described. The thermal and acid-promoted reactions of the permethylated 2-thia-3- iminobicyclo [2.2. 0] hex-bene 2 to monocyclic isomers are reported.
![1,4,5,6-tetramethyl-2-thia-3-(phenylimino)bicyclo[2.2.0]hex-5-ene Structure](https://image.chemsrc.com/caspic/084/81045-14-9.png)
![1,2,2a,8b-tetramethyl-4H-cyclobuta[c]quinoline-3-thione Structure](https://image.chemsrc.com/caspic/036/81045-15-0.png)
