title: Simple aza-conjugate addition methodology for the synthesis of isoindole nitrones and 3,4-dihydroisoquinoline nitrones.
abstract: Aryl-aldehydes containing ortho-substituted α,β-unsaturated carboxylic acid derivatives react with hydroxylamine to afford reactive N-hydroxy-carbinolamine intermediates that undergo intramolecular aza-conjugate addition reactions to afford isoindole nitrones and 3,4-dihydroisoquinoline nitrones in good yield. Conditions have been developed to reduce these isoindole nitrones to their corresponding hydroxylamine, enamine, and amine derivatives. Isoindole nitrones react with dimethyl acetylenedicarboxylate (DMAD) via a [4 + 2]-cycloaddition/deamination pathway to afford substituted naphthalene derivatives, while 3,4-dihydroisoquinoline nitrones react with DMAD via a [1,3]-dipolar cycloaddition pathway to afford tricyclic heteroarenes.
authors: Department of Chemistry, University of Bath , Bath, BA2 7AY, U.K.
authors: Lucy R
authors: LR
authors: Peacock
authors: Robert S L
authors: RS
authors: Chapman
authors: Adam C
authors: AC
authors: Sedgwick
authors: Mary F
authors: MF
authors: Mahon
authors: Dominique
authors: D
authors: Amans
authors: Steven D
authors: SD
authors: Bull