Intramolecular Diels–Alder reaction in the synthesis of 5-arylisoxazolylmethyl- and 4,5-dichloroisothiazolylmethyl-3a,6-epoxyisoindol-3-ones

The reaction of 5-arylisoxazolyl- and 4,5-dichloroisothiazolylallylamines with pyromucic acid chlorides (2-furoyl and 5-methyl-2-furoyl chlorides) was studied. The reaction proceeds via the initial acylation of the allylamine nitrogen atom and the subsequent spontaneous intramolecular Diels–Alder reaction involving the furan ring of intermediate N-furoylamides with the formation of a single diastereomer of 3a,6-epoxyisoindol-3-ones.