Skeletal remodeling of chalcone-based pyridinium salts to access isoindoline polycycles and their bridged derivatives

Abstract

A novel skeletal remodeling strategy to transform chalcone-based pyridinium salts into structurally intriguing polycyclic isoindolines was achieved through a dearomative ring-opening/ring-closing sequence.

Recent progress in the chemistry of β-aminoketones

“…Recently, researchers have focused on employing these reaction approaches to prepare a series of bicyclic aza-sugars 102-105 with glycosidic heteroatoms. 129 A sequence of reactions involving the synthesis of polycyclic isoindolines was efficiently developed by Wang et al 144 Thus, a series of tetrahydropyrido-isoindoles 110 was synthesized by treatment of chalcone-based pyridinium salts 109 with piperidine through ring-opening/ring-closure reactions. Two main factors that may affect the deconstruction of the pyridinium motif were dened as the exceptional binding of unstable in situ-formed cyclic b-aminoketones and the instability of the produced N,N-ketals.…”

“…Also, the oxidative cyclization in the presence of iodine gave the acetyl furan analog 254 , and deacetylation of one acetyl group in the presence of InCl 3 catalyst gave compound 255 in 76% yield (Scheme 61). 144…”

“…Product 259 was obtained through the reduction process followed by Michael addition in a sequence of reductive cyclization (Scheme 63). 144…”

Advances in chromone-based reactants in the ring opening and skeletal reconstruction reaction: access to skeletally diverse salicyloylbenzene/heterocycle derivatives

“…This strategy rapidly and reliably achieves skeletal diversity by remodifying the core framework, and is of great importance in the synthetic community. 69…”

Divergent Reaction of Activated Pyridines with α,α-Difluorinated gem-Diols: Regioselective Synthesis of gem-Difluorinated Dihydropyridines and Dihydropyridones

“…Dihydro-pyridines and pyridones are privileged heterocyclic scaffolds in mainstream organic chemistry . They are also extensively used as advanced synthetic intermediates for complex targets . Obviously, modular access to gem -difluorinated dihydropyridines and pyridones would have profound implications in contemporary synthesis.…”