Development of Gold-catalyzed [4+1] and [2+2+1]/[4+2] Annulations between Propiolate Derivatives and Isoxazoles
作者:Rajkumar Lalji Sahani、Rai-Shung Liu
DOI:10.1002/anie.201610665
日期:2017.1.19
new gold‐catalyzed annulations of isoxazoles with propiolates have been developed. Most isoxazoles follow an initial O attack on the alkyne to afford a [4+1] annulation product. This process results in a remarkable alkyne cleavage of initial propiolates. Unsubstituted isoxazoles proceed through an N attack step to yield formal [2+2+1]/[4+2] annulation products. These two annulation products arise initially
Photocycloaddition of aromatic and aliphatic aldehydes to isoxazoles: Cycloaddition reactivity and stability studies
作者:Axel G Griesbeck、Marco Franke、Jörg Neudörfl、Hidehiro Kotaka
DOI:10.3762/bjoc.7.18
日期:——
The first photocycloadditions of aromatic and aliphatic aldehydes to methylated isoxazoles are reported. The reactions lead solely to the exo-adducts with high regio- and diastereoselectivities. Ring methylation of the isoxazole substrates is crucial for high conversions and product stability. The 6-arylated bicyclic oxetanes 9a-9c were characterized by X-ray structure analyses and showed the highest
报道了芳香族和脂肪族醛对甲基化异恶唑的首次光环加成反应。该反应仅导致具有高区域选择性和非对映选择性的外加合物。异恶唑底物的环甲基化对于高转化率和产品稳定性至关重要。6-芳基化双环氧杂环丁烷 9a-9c 通过 X 射线结构分析表征并显示出最高的热稳定性。由异恶唑形成的所有氧杂环丁烷都对酸高度敏感且热不稳定。对原始底物的裂解占主导地位,异恶唑衍生的氧杂环丁烷显示 T 型光致变色。
[EN] OXINDOLE DERIVATIVES AND THEIR USE AS PHOSPHODIESTERASE TYPE 2 INHIBITORS<br/>[FR] DERIVES D'OXINDOLE ET LEUR UTILISATION COMME INHIBITEURS DE LA PHOSPHODIESTERASE DE TYPE 2
申请人:PFIZER PROD INC
公开号:WO2005041957A1
公开(公告)日:2005-05-12
The present invention provides compounds, methods and kits for treatment of disease states or disorders mediated by PDE2. Oxindole derivatives are provided which have therapeutic use and as PDE2 inhibitors.
Gold-catalyzed [4+3]- and [4+2]-annulations of 3-en-1-ynamides with isoxazoles <i>via</i> novel 6π-electrocyclizations of 3-azahepta trienyl cations
作者:Sovan Sundar Giri、Rai-Shung Liu
DOI:10.1039/c8sc00232k
日期:——
New gold-catalyzed [4+3]-annulations of 3-en-1-ynamides with isoxazoles afford 4H-azepines efficiently; this process involves 6π electrocyclizations of gold-stabilized 3-azaheptatrienyl cations. In the presence of Zn(OTf)2, the resulting 4H-azepines undergo skeletal rearrangement to furnish substituted pyridine derivatives. We subsequently develop new catalytic [4+2]-annulations between the same 3-en-1-ynamides
Gold-catalyzed bicyclic annulations of 4-methoxy-1,2-dienyl-5-ynes with isoxazoles to form indolizine derivatives <i>via</i> an Au-π-allene intermediate
作者:Antony Sekar Kulandai Raj、Kuo-Chen Tan、Liang-Yu Chen、Mu-Jeng Cheng、Rai-Shung Liu
DOI:10.1039/c9sc00735k
日期:——
Gold-catalyzed bicyclic annulations of 4-methoxy-1,2-dienyl-5-ynes with isoxazoles afford indolizine derivatives with a structural rearrangement. The mechanism of these new annulations does not involve α-imino gold carbenes generated from gold π-alkyne intermediates. We postulate alkyne attack on gold π-allenes, yielding vinyl gold carbenes. These newly generated carbenes react with isoxazole derivatives