Thermal [2 + 2]-cycloaddition between silylalkynes and allenylphenols followed by the nucleophilic addition of water: metal-free and economical synthesis of arylcyclobutenals
作者:Shohei Ohno、Ramon Francisco Avena、Hiroshi Aoyama、Hiromichi Fujioka、Mitsuhiro Arisawa
DOI:10.1039/c9gc04184b
日期:——
A novel thermal [2 + 2]-cycloaddition between silylalkynes and allenylphenols to form a cyclobutachromene intermediate, followed by the nucleophilic addition of water to yield functionalized arylcyclobutenals.
Pauson–Khand reactions of functionalized allenes with different alkynes give cyclopentenones with generally high regio- and stereoselectivities. The allenes react through their external double bonds, giving cyclopentenones with exocyclic double bond at their β positions and predominantly with E stereochemistry. Some intramolecularreactions with allenynes connected through aromatic rings are described
具有不同炔烃的官能化丙二烯的 Pauson-Khand 反应产生具有通常高区域选择性和立体选择性的环戊烯酮。丙二烯通过它们的外部双键反应,得到在其 β 位置具有环外双键的环戊烯酮,主要是 E 立体化学。描述了通过芳环连接的丙炔的一些分子内反应。这些以中等至良好的产率得到相应的杂环。
One‐Pot Synthesis of 1,2,3‐Triazolo Polycyclic Systems via Copper‐Catalyzed/TsOH‐Promoted Tandem Annulation of 1,6‐Allenynes with Organic Azides
A copper-catalyzed/TsOH-promoted one-pot tandem annulation of 1,6-allenynes with organicazides was reported, providing N-allyl 1,2,3-triazole-fused structures in moderate to excellent yields under mild reaction conditions. Moreover, the late-stage diversification of the N-allyl products can be realized by chemoselectively reducing to the N-alkyl counterparts.
The gold-catalysed reactions of alleneamides give different products depending on the substrate and the reaction conditions. In particular, N-(2-alkynylphenyl)-N-allenyltosylamides give benzazepines when using gold(III) catalysts in the presence of nucleophiles. This sequential process may follow two different reaction pathways, and these are discussed. Metal coordination to the alkyne followed by
An unprecedented copper-catalyzed tandem cross-coupling/[2 + 2] cycloaddition of 1,6-allenynes with diazo compounds was reported, chemo- and regioselectively providing 3-azabicyclo[5.2.0] frameworks in moderate to excellent yields under mild reactionconditions. Moreover, the products readily convert to highly functionalized quinolines via oxidative radical rearrangement.