Base- and Ligand-free Room-Temperature Synthesis of N-Fused Heteroaromatic Compounds via the Transition Metal-Catalyzed Cycloisomerization Protocol
摘要:
A new practical method for the synthesis of N-fused heterocycles via the transition metal-catalyzed cycloisomerization of heterocyles possessing a propagyl group has been developed. This very mild, base- and ligand-free method allows for the synthesis of diverse fused heterocyclic cores in good to excellent yields.
Multisubstituted N-fused heterocycles via transition metal-catalyzed cycloisomerization protocols
作者:Ilya V. Seregin、Alex W. Schammel、Vladimir Gevorgyan
DOI:10.1016/j.tet.2008.04.023
日期:2008.7
multisubstituted N-fused heterocycles have been developed. It was demonstrated that 1,3-disubstituted N-fused heterocycles, including indolizines, pyrroloquinoxalines, and pyrrolothiazoles can easily be synthesized via an exceptionally mild and efficient method involving a novel silver-catalyzed cycloizomerization of propargyl-containing heterocycles. Alternatively, 1,2-disubstitutedheterocycles can be accessed
Synthetic and Mechanistic Studies on the Solvent-Dependent Copper-Catalyzed Formation of Indolizines and Chalcones
作者:María José Albaladejo、Francisco Alonso、María José González-Soria
DOI:10.1021/acscatal.5b00417
日期:2015.6.5
formation from aldehydes and alkynes, a new reaction pathway involving propargyl amines as intermediates that do not undergo rearrangement is presented. The formation of indolizines or chalcones is driven by inductive and solvent effects, with a wide array of both being reported. In both reactions, the nanoparticulate catalyst has been shown to be superior to some commercially available copper catalysts
In the presence of deuterium oxide benzaldehyde () and substituted benzaldehydes likewise possessing lowest triplet states of (n,w*) character yield formyl-deuteriated benzaldehydes by fast and efficient photoreactions. Quantum yields of formation of 7-deuterio benzaldehyde in solvent acetonitrile-deuterium oxide 3:1 are 0.57 at 313 nm), 0.54 at 331 nm. 0.62 at 365 nm, and in acetone-deuterium oxide
N-Heterocyclic Carbene Catalyzed <i>C</i>-Glycosylation: A Concise Approach from Stetter Reaction
作者:Seenuvasan Vedachalam、Shi Min Tan、Hui Ping Teo、Shuting Cai、Xue-Wei Liu
DOI:10.1021/ol202959y
日期:2012.1.6
Described herein is the first example of an organocatalytic approach for acylanion addition to the anomeric carbon of 2-nitroglucal using an N-heterocycliccarbene catalyst. Control over the reaction conditions gives β-selective and nitro-eliminated C-glycosides, providing opportunities to produce new classes of C-glycoside.
On the Validity of Au-vinylidenes in the Gold-Catalyzed 1,2-Migratory Cycloisomerization of Skipped Propargylpyridines
作者:Yuanzhi Xia、Alexander S. Dudnik、Yahong Li、Vladimir Gevorgyan
DOI:10.1021/ol1024794
日期:2010.12.3
A mechanism of the Au-catalyzed cycloisomerization of propargylpyridines has been investigated. Both DFT computational and experimental results strongly support generation of a Au-carbene via a cyclization/proton transfer sequence over the previously proposed path involving a Au-vinylidene intermediate. For the beta-Si-substituted Au-carbene (G = SiR3), a 1,2-Si migration was shown to be kinetically favored over a 1,2-H shift. This study highlights the importance of alternative pathways that could explain reactivities commonly attributed to an alkyne-vinylidene isomerization in Au catalysis.