Stereoselective hetero Diels–Alder reaction of selenoaldehydes with pentavalent phosphole chalcogenides

Stereoselective hetero Diels–Alder reaction of selenoaldehydes, generated by thermal retro Diels–Alder reaction of anthracene cycloadducts, with pentavalent 3,4-dimethylphosphole chalcogenides at 110 °C in toluene to give the corresponding [4+2] cycloadducts as a single diastereoisomer in good yields, accompanied by a slight scrambling of chalcogen atoms. Higher reaction temperature led to an increase of the scrambling between chalcogen atoms.