Copper(0)/PPh<sub>3</sub>-Mediated Bisheteroannulations of <i>o</i>-Nitroalkynes with Methylketoximes Accessing Pyrazo-Fused Pseudoindoxyls
作者:Huanxin Meng、Zhenhua Xu、Zhonghua Qu、Huawen Huang、Guo-Jun Deng
DOI:10.1021/acs.orglett.0c02180
日期:2020.8.7
A copper(0)/PPh3-mediated cascade bisheteroannulation reaction of o-nitroalkynes with methylketoximes has been developed that provides viable access to a diverse range of pyrazo-fused pseudoindoxyl compounds. Synthetically useful functional groups including sensitive C–I bonds are compatible with this system. Mechanistic studies suggest a reaction cascade involving sequential PPh3-mediated deoxygenative
Intramolecular Iodine-Mediated Oxygen Transfer from Nitro Groups to C≡C Bonds
作者:Inga Cikotiene
DOI:10.1002/ejoc.201200100
日期:2012.5
from nitrogroups to C≡C bonds has been achieved by employment of iodine monochloride or molecular iodine. The precursors are heterocyclic, aromatic or acyclic compounds, each bearing a nitrogroup ortho to an internal alkyne. The developed methodology is general for the preparation of a wide range of fused isoxazoles, each bearing a carbonyl function in the fifth position in the isoxazole ring. It
Interrupting the [Au]-Catalyzed Nitroalkyne Cycloisomerization: Trapping the Putative α-Oxo Gold Carbene with Benzo[<i>c</i>]isoxazole
作者:Pawan S. Dhote、Chepuri V. Ramana
DOI:10.1021/acs.orglett.1c00539
日期:2021.4.2
interrupted by possible trapping of the postulated intermediate α-oxo gold carbene with an external nucleophile such as benzo[c]isoxazole (anthranil). At the outset, this provides a simple synthesis of highly functionalized 3-acyl-(2-formylphenyl)-2H-indazoles with the sequential C–O, C–N, and N–N bond formations. This provides indirect support for the existence of α-oxo gold carbenes in the [Au]-catalyzed internal
通过假想的中间体α-氧代金卡宾可能被外部亲核试剂(例如苯并[ c ]异恶唑(蒽))捕获,从而中断了导致蒽基的2-炔基硝基苯的Au催化硝基炔环异构化。首先,它提供了具有连续C–O,C–N和N–N键形成的高度官能化的3-酰基-(2-甲酰基苯基)-2 H-吲唑的简单合成方法。这为在α-催化的炔炔的内部氧化还原过程中α-氧羰金的存在提供了间接支持。
Catalytic asymmetric formal [3+2] cycloaddition of isatogens with azlactones to construct indolin-3-one derivatives
作者:Lihua Xie、Yi Li、Shunxi Dong、Xiaoming Feng、Xiaohua Liu
DOI:10.1039/d0cc06418a
日期:——
A number of enantioenriched indolin-3-one derivatives were readily obtained by chiral guanidine-catalyzed [3+2] cycloaddition of isatogens with azlactones.
Electrochemically Enabled Selenium Catalytic Synthesis of 2,1-Benzoxazoles from <i>o</i>-Nitrophenylacetylenes
作者:Lin-Wei Wang、Yu-Feng Feng、Hong-Min Lin、Hai-Tao Tang、Ying-Ming Pan
DOI:10.1021/acs.joc.1c00012
日期:2021.11.19
reported an electrochemically mediated method for the preparation of 2,1-benzoxazoles from o-nitrophenylacetylenes. Different from the traditional electrochemical reduction of nitro to nitroso, the nitro group directly underwent a cyclization reaction with the alkyne activated by selenium cation generated by the anodic oxidation of diphenyldiselenide and finally produced the desired products.