Synthesis of Spiro[benzo[d][1,3]oxazine-4,4′-isoquinoline]s via [4+1+1] Annulation of N-Aryl Amidines with Diazo Homophthalimides and O2

Synthesis of spiro [benzo[d][1,3]oxazine-4,4 '- isoquinoline]s through a unique [4+1+1] annulation of N-aryl amidines with diazo homophthalimides and O-2 is presented. This unprecedented spirocyclization reaction features readily obtainable substrates, structurally and pharmaceutically attractive products, a cost-free and clean oxygen source, sustainable reaction medium, tolerance of a broad spectrum of functional groups, and an interesting reaction mechanism based on sequential C(sp(2))-H/ C(sp(3))-H bond cleavage and oxygen insertion.

Automated summary

A unique [4+1+1] annulation reaction of N-aryl amidines with diazo homophthalimides and O-2 enables the synthesis of structurally and pharmaceutically attractive spiro [benzo[d][1,3]oxazine-4,4'-isoquinoline] compounds. This unprecedented reaction exhibits readily obtainable substrates, a cost-free and clean oxygen source, a sustainable reaction medium, broad tolerance of functional groups, and an interesting reaction mechanism based on sequential C(sp(2))-H/ C(sp(3))-H bond cleavage and oxygen insertion.