Palladium-catalysed dual ring-opening [3 + 4] annulation of isatoic anhydrides with cyclic iodoniums to build tribenzo[b,d,f]azepines and a mechanistic DFT study

Abstract

A dual ring-opening, decarboxylative/decarbonylative [3 + 4] annulation of readily available (6-membered) isatoic anhydrides with (5-membered) cyclic iodoniums to efficiently build (7-membered) tribenzo[b,d,f]azepines through Pd(0) catalysis is disclosed. The tandem...

Sequential annulation of bidentate diamines for modular access to N-fused/helical/spiro-carbazole scaffolds

“…Other solvents such as MeOH, MeCN, and 1,4-dioxane were much less effective than DMF (entries [10][11][12]. Lastly, some other bases were tested but none of them enhanced the yield (entries [13][14][15]. It is noted that the eight-membered byproduct 6a′ was not detected (n.d.) throughout the entire optimization process.…”

“…11 For example, Wen 12 and Nachtsheim, 13 respectively, reported [4 + 1] annulative dual C–N coupling of anilines with cyclic diaryliodonium salts using Cu and Pd catalysis, while the reaction of ortho -substituted anilines has not been documented. Recently, our group reported the synthesis of benzo[ c ]cinnolines, 14 tribenzo[ b , d , f ]azepines, 15 and triphenylenes 16 using cyclic diaryliodonium salts. The retrosynthetic analysis of the N-fused Cz skeleton suggests that it could be accessed by intramolecular deaminative cyclization of N -aminoaryl carbazole which could be prepared from a cyclic diaryliodonium salt and a diamine (Scheme 1c).…”