to afford bicyclic pyridines. Careful screening of nitrile components revealed that a C[triple chemical bond]C triple bond or heteroatom substituents, such as methoxy and methylthio groups, proved to act as the coordinating groups, whereas C==C or C==O doublebonds and amino groups failed to promote cycloaddition. This suggests that coordinating groups with multiple pi-bonds or lone pairs are essential
Acetylation of 5,6-dihydro-4H-1,2-oxazines with an acetyl bromide/acetic anhydride mixture provides a general and quite simple procedure for the synthesis of N-acetyl-5,6-dihydro-2H-1,2-oxazines.
Nickel-Catalyzed [2+2+2] Cycloaddition of Alkyne-Nitriles with Alkynes Assisted by Lewis Acids: Efficient Synthesis of Fused Pyridines
作者:Xu You、Xin Xie、Gaonan Wang、Meijun Xiong、Renhong Sun、Haoyi Chen、Yuanhong Liu
DOI:10.1002/chem.201603829
日期:2016.11.14
A Ni/BPh3 catalyzed [2+2+2] cycloaddition of alkyne‐nitriles with alkynes has been developed, which provides an efficient route to fused pyridines under mild reaction conditions. Mechanistic studies indicate that an azanickelacycle via heterocoupling of an alkyne with a nitrile moiety is possibly formed as a key reaction intermediate. The Lewisacid catalyst is crucial to the successful transformation
Generation of the Methoxycarbonyl Radical by Visible-Light Photoredox Catalysis and Its Conjugate Addition with Electron-Deficient Olefins
作者:Yuriy Slutskyy、Larry E. Overman
DOI:10.1021/acs.orglett.6b00895
日期:2016.6.3
a 1,4-dicarbonyl structural motif by a conjugate addition of the methoxycarbonyl radical to reactive Michael acceptors. The regioselectivity of the addition of this alkoxyacyl radical species to electron-deficient olefins is heavily influenced by the electronic nature of the acceptor, behavior similar to that exhibited by nucleophilic alkyl radicals.
Synthesis of Tricyclic Fused 3-Aminopyridines through Intramolecular Co<sup>I</sup>-Catalyzed [2+2+2] Cycloaddition between Ynamides, Nitriles, and Alkynes
Three‐ring circus: An expedient route to tricyclicfused2‐trimethylsilyl‐3‐aminopyridines exhibiting unprecedented skeletons is described. The key step is a very efficient cobalt‐catalyzed [2+2+2] cycloaddition of a polyunsaturated compound displaying an ynamide, an alkyne, and a nitrile functionality (see picture).