Intermolecular ene insertion of photochemically generated thioaldehyde MeO2CCH=S with β-pinene occurs at room temperature to give the sulfide 2c. The internal ene insertion of thioaldehyde 6 affords a six-membered carbocycle 9 rather than the seven-membered sulfide 10 which would correspond to the regiochemistry of the intermolecular process (eq 5, 6). Likewise, internal Diels-Alder trapping occurs without a dominant role for the regiochemical preferences seen in intermolecular reactions. Desulfurization of typical internal adducts such as 25,26 or 29,30 affords 31 and 33,34, respectively.
All Science Journal Classification (ASJC) codes
- Organic Chemistry