Organoselenium-Catalyzed Mild Dehydration of Aldoximes: An Unexpected Practical Method for Organonitrile Synthesis
摘要:
Areneselenenic acids (ArSeOH), readily generated from diaryl diselenides and H2O2 by in situ oxidation, were found to be effective and reusable catalysts for dehydration of aldoximes, leading to a practical and scalable preparation of useful organonitriles under mild conditions.
Metal-free visible-light induced cyclization/substitution cascade reaction of alkyne-tethered cyclohexadienones and diselenides: access to 5-hydroxy-3-selenyl-4a,8a-dihydro-2<i>H</i>-chromen-6(5<i>H</i>)-ones
A simple and efficient Se-radical triggered cyclization/substitution cascadereaction of alkyne-tethered cyclohexadienones to afford 5-hydroxy-3-selenyl-4a,8a-dihydro-2H-chromen-6(5H)-ones has been developed. This transformation via the 3,5-diselenyl-4a,8a-dihydro-2H-chromen-6(5H)-one intermediate followed by hydrolysis in the presence of CsOAc affords the desired product 3. The resulting products
An oxidative trifunctionalization of arylalkynoates has been devised via the chalcogenide radical triggered intramolecular 1,4-aryl migration/decarboxylation cascade to prepare 1,1-dichalcogenide tetrasubstituted alkenes in high yields (up to 98 %). This operationally simple reaction proceeds under metal-free conditions, can be executed on gram scale, and highlights formal 1,1-difunctionalization
d selenylation/cyclization of enaminones have been realized for the practical synthesis of 3‐selanyl‐4H‐chromen‐4‐ones. This reaction is performed in the mild conditions, no transition metal catalyst or photocatalysts and no additional oxidants are required. In addition, the 3‐selanyl‐4H‐chromen‐4‐ones could be easily converted to selanyl‐functionalized pyrimidines by reacting with benzamidine substrates
已经实现了简单而有效的可见光促进的烯胺酮的硒化/环化反应,可实际合成3-Selanyl-4 H -chromen-4- 。该反应在温和的条件下进行,不需要过渡金属催化剂或光催化剂,也不需要其他的氧化剂。此外,通过与苯甲idine底物反应,可以很容易地将3-selanyl-4 H -chromen-4 -ones转化为selanyl-functionalized嘧啶。
Alkene <i>versus</i> alkyne reactivity in unactivated 1,6-enynes: regio- and chemoselective radical cyclization with chalcogens under metal- and oxidant-free conditions
作者:Mohana Reddy Mutra、Vishal Suresh Kudale、Jing Li、Wu-Hsun Tsai、Jeh-Jeng Wang
DOI:10.1039/d0gc00321b
日期:——
light-promoted alkene vs. alkyne regio- and chemoselective radical cascade cyclization of electronically unbiased 1,6-enynes with chalcogens to synthesize substituted pyrrolidines bearing chalcogens. The reaction generated three new bonds, namely, C–SO2, C–C, and C–Se under extremely mild conditions. Furthermore, we achieved regio- and chemoselective mono-addition of aromatic thiophenols with unactivated 1,6-enynes
A novel, practical and metal-free approach for the regioselective selenation of coumarins employing (bis(trifluoroacetoxy)iodo)benzene (PIFA) at room temperature is presented. The developed method is suitable for a wide substrate scope and affords 3-selenyl coumarins in good to excellent yields with high selectivity. A radical mechanism is proposed for this new transformation. Furthermore, the application