Internal Thioaldehyde Trapping by Enes and Dienes

Article abstract of DOI:10.1021/jo00245a018

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 and33,34, respectively.