Vicinal diamines are key motifs widely-found in many pharmaceuticals and biologically active molecules.An appealing approach for synthesizing these molecules is the amination of enamines,but few examples have been exp...Vicinal diamines are key motifs widely-found in many pharmaceuticals and biologically active molecules.An appealing approach for synthesizing these molecules is the amination of enamines,but few examples have been explored.With the utilization of nitrogen-centered radicals(NCRs),here we present the development of a dual bio-/photo-catalytic system for achieving enantioselective hydroamination of enamides,which can give easy access to diverse enantioenriched vicinal diamines.These reactions progress efficiently under green light excitation and exhibit excellent enantioselectivities(up to>99%enantiomeric excess).Mechanistic studies uncovered the synergistic effect of the enzyme and the externally added organophotoredox catalyst Rhodamine B(RhB).This work demonstrates the effectiveness of photobiocatalysis to generate and control high-energy radical intermediates,addressing a long-standing challenge in chemical synthesis.展开更多
A highly efficient Pd\|BMImCl/TiO\-\%y\%\|SiO\-\%x\% catalyst system synthesized through sol\|gel method from palladium complex, ionic liquid, titanate and silicate esters was found for the oxidative carbonylation of ...A highly efficient Pd\|BMImCl/TiO\-\%y\%\|SiO\-\%x\% catalyst system synthesized through sol\|gel method from palladium complex, ionic liquid, titanate and silicate esters was found for the oxidative carbonylation of amines. The catalyst efficiency was much higher than that reported in previous papers and the TOF number reached to 10 372 when catalyst 0.05%Pd\|4.6%BMImCl/TiO\-\%y\%\|SiO\-\%x\% was used. The usability of ionic liquid was the key point for preparation of this catalyst system because of its high dissolvability to palladium complex and affording appropriate micro\|environment for the reaction. The synergism among palladium complex, ionic liquid, titanate and silicate was the main reason for the high catalytic activity of the catalyst system. BET, AES and XRD were used to characterized the catalysts in detail.展开更多
为了解决报废偏二甲肼再利用问题,使偏二甲肼经烷基化、酰基化、脱氢,合成了八种具有较低熔点的饱和脂肪族胺基酰亚胺化合物。研究了胺基酰亚胺的结构、熔点和热分解温度。红外分析表明,酰亚胺基团N-上的LP与酰基π轨道产生共轭效应,形...为了解决报废偏二甲肼再利用问题,使偏二甲肼经烷基化、酰基化、脱氢,合成了八种具有较低熔点的饱和脂肪族胺基酰亚胺化合物。研究了胺基酰亚胺的结构、熔点和热分解温度。红外分析表明,酰亚胺基团N-上的LP与酰基π轨道产生共轭效应,形成两个共振结构N C O-和N-C O。酰基上的取代烷基给电诱导能力的强弱对酰亚胺基团这两个共振结构的特征吸收峰位置有明显影响,给电诱导能力越弱,则N C O-和N-C O红外吸收的频率越高。动态DSC分析表明,胺基碳链对饱和脂肪族胺基酰亚胺热分解活性的影响不明显,而延长酰基碳链可显著提高热分解活性。展开更多
文摘Vicinal diamines are key motifs widely-found in many pharmaceuticals and biologically active molecules.An appealing approach for synthesizing these molecules is the amination of enamines,but few examples have been explored.With the utilization of nitrogen-centered radicals(NCRs),here we present the development of a dual bio-/photo-catalytic system for achieving enantioselective hydroamination of enamides,which can give easy access to diverse enantioenriched vicinal diamines.These reactions progress efficiently under green light excitation and exhibit excellent enantioselectivities(up to>99%enantiomeric excess).Mechanistic studies uncovered the synergistic effect of the enzyme and the externally added organophotoredox catalyst Rhodamine B(RhB).This work demonstrates the effectiveness of photobiocatalysis to generate and control high-energy radical intermediates,addressing a long-standing challenge in chemical synthesis.
文摘A highly efficient Pd\|BMImCl/TiO\-\%y\%\|SiO\-\%x\% catalyst system synthesized through sol\|gel method from palladium complex, ionic liquid, titanate and silicate esters was found for the oxidative carbonylation of amines. The catalyst efficiency was much higher than that reported in previous papers and the TOF number reached to 10 372 when catalyst 0.05%Pd\|4.6%BMImCl/TiO\-\%y\%\|SiO\-\%x\% was used. The usability of ionic liquid was the key point for preparation of this catalyst system because of its high dissolvability to palladium complex and affording appropriate micro\|environment for the reaction. The synergism among palladium complex, ionic liquid, titanate and silicate was the main reason for the high catalytic activity of the catalyst system. BET, AES and XRD were used to characterized the catalysts in detail.
文摘为了解决报废偏二甲肼再利用问题,使偏二甲肼经烷基化、酰基化、脱氢,合成了八种具有较低熔点的饱和脂肪族胺基酰亚胺化合物。研究了胺基酰亚胺的结构、熔点和热分解温度。红外分析表明,酰亚胺基团N-上的LP与酰基π轨道产生共轭效应,形成两个共振结构N C O-和N-C O。酰基上的取代烷基给电诱导能力的强弱对酰亚胺基团这两个共振结构的特征吸收峰位置有明显影响,给电诱导能力越弱,则N C O-和N-C O红外吸收的频率越高。动态DSC分析表明,胺基碳链对饱和脂肪族胺基酰亚胺热分解活性的影响不明显,而延长酰基碳链可显著提高热分解活性。
