Pyridinium salts—versatile reagents for the regioselective synthesis of functionalized thiazocino[2,3-b]indoles by tandem dinucleophilic reactions of thiooxindoles
作者:Mostafa Kiamehr、Firouz Matloubi Moghaddam、Pavel V. Gormay、Volodymyr Semeniuchenko、Alexander Villinger、Peter Langer、Viktor O. Iaroshenko
DOI:10.1016/j.tet.2012.09.059
日期:2012.11
The reaction of thiooxindoles with various 2- and 3-substituted pyridinium salts afforded a variety of functionalized thiazocinoindoles. The products have been prepared in good to excellent yields by regioselective dinucleophilic C/S-cyclocondensation of thiooxindoles with pyridinium salts.
Enantioselective N-heterocyclic carbene-catalyzed nucleophilic dearomatization of alkyl pyridiniums
作者:Darrin M. Flanigan、Tomislav Rovis
DOI:10.1039/c7sc02648j
日期:——
NHC-catalyzed nucleophilic dearomatization of alkyl pyridiniums has been achieved to generate 1,4-dihydropyridines with high enantioselectivity. This is a rare example of catalytic, asymmetric addition of a nucleophile to the activated pyridinium that prefers C-4 functionalization leading to the 1,4-dihydropyridine with high selectivity.
Divergent Reaction of Activated Pyridines with α,α-Difluorinated <i>gem</i>-Diols: Regioselective Synthesis of <i>gem</i>-Difluorinated Dihydropyridines and Dihydropyridones
The nucleophilic reactivity of α,α-difluorinated gem-diols toward activated pyridinium salts has been capitalized in a highly regioselective fashion, offering biologically relevant 1,4-dihydropyridines and 3,4-dihydro-2-pyridones adorned with the valuable gem-difluoromethylene motif. The protocol is scalable as well as high yielding and accommodates a broad range of substrates and functional groups