RESUMO
A simple and efficient base-mediated decarboxylative annulation of ynones with methyl 2-(2-bromophenyl)acetates has been developed. A broad range of benzoxepines were prepared with a broad substrate scope and high regioselectivity in moderate to excellent yields under transition-metal-free conditions. This method proceeds through a tandem [2 + 4] annulation, ring-opening decarboxylative reaction, and the intramolecular nucleophilic aromatic substitution reaction. Additionally, the key intermediates were successfully obtained and characterized unambiguously by single-crystal X-ray crystallography, which could favorably support a decarboxylative annulation mechanism. Furthermore, gram-scale reaction and synthetic applications for the further functionalization are also studied.
RESUMO
A facile and efficient base-mediated divergent annulation of methyl 2-(cyanomethyl)benzoates and conjugated ynones has been described. A broad range of 1-naphthols and xanthones were formed in moderate to excellent yields. The notable features of this protocol include readily available precursors, broad substrate scope, complete regioselectivity, and substrate-controlled divergent synthesis. The gram-scale preparation and synthetic transformations of the resulting 1-naphthols and xanthones demonstrate their utility.
Assuntos
Naftóis , Xantonas , Benzoatos , Catálise , Estrutura MolecularRESUMO
A facile and effective tandem reaction of ynones and methyl salicylates was developed to obtain a broad range of 3-acyl chromones in moderate-to-excellent yields. This protocol underwent a Michael addition and cyclization process, which exhibited easily accessible substrates, broad substrate scope, and high regioselectivity under mild and transition-metal-free conditions. Moreover, gram-scale reaction and further chemical transformation of the products were also further studied.
Assuntos
Cromonas , Elementos de Transição , Estereoisomerismo , Ciclização , SalicilatosRESUMO
A simple and effective tandem reaction of diynones and allylic alcohols was developed to afford functionalized 3-allyl-4-pyrones in moderate to excellent yields. This protocol underwent a Michael additionâClaisen rearrangementâO-cyclization process, which exhibited broad substrate tolerance, high regioselectivity, and atom economy under a metal-free condition. Moreover, functional transformation of the products was also further studied.
Assuntos
Pironas , Catálise , Ciclização , Estrutura Molecular , FosfinasRESUMO
A simple and effective annulation of ynediones and (iso)quinoline N-oxides was developed to afford various functionalized pyrrolo[2,1-a]isoquinolines and pyrrolo[1,2-a]quinolines in moderate to excellent yields. This protocol underwent a tandem [3 + 2] cycloaddition/ring-opening/N-nucleophilic addition, which exhibited high regioselectivity, broad substrate tolerance, and atom economy under catalyst-, additive-free, and air conditions. Moreover, indolizine was also successfully prepared using pyridine N-oxide.
RESUMO
N'-(3,5-Dichloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide (H2L) was used to prepare oxidovanadium(V) complex [VOL(OEt)(MeOH)] (1) and dioxidomolybdenum(VI) complex [MoO2L(OH2)]·[MoO2L(EtOH)] (2). The complexes were characterized by IR, UV-Vis, NMR spectroscopy, and single crystal X-ray diffraction. X-ray analysis indicates that the complexes are mononuclear species with the metal atoms in octahedral coordination. The complexes were studied for catalytic oxidation property on some olefins with tert-butyl hydroperoxide as oxidant.
RESUMO
An effective annulation of ynones and (iso)quinoline N-oxides was developed to deliver various functionalized 3-((iso)quinolin-1-yl)-4H-chromen-4-ones and 13H-isoquinolino[2,1-a]quinolin-13-ones in moderate to excellent yields, respectively. This protocol exhibits high regioselectivity and broad substrate scope under transition-metal-free conditions. Moreover, the key reaction intermediate was successfully isolated and determined unambiguously by single crystal X-ray crystallography.