NH₄OAc Promoted Cyclocondensation of 3-(o-Allylphenyl)pentane-1,5-diones: Synthesis of Tetracyclic Benzofused 1-Azahomoisotwistanes

Abstract

A facile two-step synthetic route for preparing the novel tetracyclic skeleton of benzofused 2,6-diaryl-1-azahomoisotwistanes 2 had been developed. The route was carried out by a one-pot tandem cross-coupling reaction of o-allylbenzaldehydes 1 with aryl methyl ketones 3, and NH(4)OAc mediated the cascade cyclocondensation reaction of the resulting 1,5-diketones 4 with the 3-o-allylphenyl group in good yield in two steps.

Construction of Sulfonyl Oxabenzo[3.3.1]bicyclic Core via Cyclocondensation of β-Ketosulfones and o-Formyl Allylbenzenes

“…Recently, we developed a one-pot easy-operational route for the synthesis of diversified carbocyclic or heterocyclic benzofused frameworks by functionalization of β-ketosulfones (α-sulfonyl ketones, 1 ) or o -formyl allylbenzenes ( o -allyl benzaldehydes, 2 ) building blocks under a series of domino benzannulation processes . With receiving significant results, we wanted to investigate the possibility of the construction of novel core systems by the combination of two scaffolds via a single-step domino transformation.…”

Synthesis of Substituted 2,3-Benzodiazepines

“…Recently, we developed a series of synthetic routes toward benzofused compounds, such as 1-azahomoisotwistanes, benzodioxepanes, benzo­[ g ]­indazoles, benzo­[ g ]­chrysenes, 2-naphthols, isochromenes, and isoquinolines, by using commercially available isovanillin ( 2a ) as a starting material. All of the compounds were derived from the versatile 2-allylbenzaldehyde ( 4 ), which was easily prepared via a three-step synthesis with moderate overall yields by a reaction procedure of O-allylation and Claisen rearrangement followed by O-alkylation.…”

Construction of Sulfonyl Dihydrobenzo[c]xanthen-7-ones Core via NH4OAc/PdCl2/CuCl2-Mediated Double Cyclocondensation of α-Sulfonyl o-Hydroxyacetophenones with 2-Allylbenzaldehydes

“…Recently, we explored a one-pot facile-operational route for the preparation of different benzofused carbo- or heterocyclic skeletons, including nitrated or dioxa-benzobicycles, , tetrahydrocyclobuta­[ a ]­naphthalenes, and benzofused azahomoisotwistanes by the concise functionalization of 2-allylbenzaldehydes ( o -allyl benzaldehydes) under cascade annulation procedures. On the basis of these valuable results, we plan to construct the core skeleton of xanthone by the combination of 2-allylbenzaldehydes and o -hydroxyacetophenones under Knoevenagel/Wacker/aldol conditions via a one-step cascade conversion.…”