A NHC-catalyzed hypervalent iodine reagents and transition-metal free redox-neutral dearomatization of phenols is reported.This protocol provides an efficient access for highly congested quaternatry carbon centers con...A NHC-catalyzed hypervalent iodine reagents and transition-metal free redox-neutral dearomatization of phenols is reported.This protocol provides an efficient access for highly congested quaternatry carbon centers construction.It also features operationally simplicity,mild reaction conditions and good functional group tolerance.Moreover,the reported procedure can be easily emplified to 1 g scale.Mechanism study reveals the dearomative transformation possibly undergoes a single electron transfer process with NHC radical cation as a reactive intermediate.展开更多
An intriguing Brønsted acid-catalyzed 1,6-hydrophosphination of in situ generated propargylic para-quinone methides(p-QMs)and aza-para-quinone methides(aza-p-QMs)with H-phosphorus oxides via dehydration/1,6-addit...An intriguing Brønsted acid-catalyzed 1,6-hydrophosphination of in situ generated propargylic para-quinone methides(p-QMs)and aza-para-quinone methides(aza-p-QMs)with H-phosphorus oxides via dehydration/1,6-addition under ultrasonic irradiation is described.This methodology provides a rapid and green approach for the construction of diarylmethyl phosphorus oxides bearing phosphorus-substituted quaternary carbon centers in high yields(up to 98%yield)within merely 5min.This environmentally benign protocol represents a unique example of 1,6-conjugate additions of propargylic p-QMs and aza-p-QMs for site-selective C-P bond formation in an operationally simple and atom-economical manner.The use of readily available Brønsted acid catalyst,operationally simplicity,high yields,and high atom economy make this protocol very facile,practical,easily scaled-up and environmentally friendly.展开更多
Tartaric acid, oxalic acid, glucose, and fructose are highly important compounds. A comprehensive study of these substances is fascinating from a scientific perspective. They are key components found in wine, vegetabl...Tartaric acid, oxalic acid, glucose, and fructose are highly important compounds. A comprehensive study of these substances is fascinating from a scientific perspective. They are key components found in wine, vegetables, and fruits. Understanding the isotopic compositions in organic compounds is crucial for comprehending various biochemical processes and the nature of substances present in different natural products. Tartaric acid, oxalic acid, glucose, and fructose are widely distributed compounds, including in vegetables and fruits. Tartaric acid plays a significant role in determining the quality and taste properties of wine, while oxalic acid is also prevalent but holds great interest for further research, especially in terms of carbon isotopic composition. We can unveil the mechanisms of processes that were previously impossible to study. Glucose and fructose are the most common monosaccharides in the hexose group, and both are found in fruits, with sweeter fruits containing higher amounts of these substances. In addition to fruits, wheat, barley, rye, onions, garlic, lentils, peppers, dried fruits, beans, broccoli, cabbage, tomatoes, and other foods are also rich sources of fructose and glucose. To determine the mass fraction of the carbon-13 isotope in these compounds, it is important to study their changes during natural synthesis. These compounds can be modified with a carbon center. According to the existing isotopic analysis method, these compounds are converted into carbon oxide or dioxide [1]. At this point, the average carbon content in the given compound is determined, but information about isotope-modified centers is lost. Dilution may occur through the transfer of other carbon-containing organic compounds in the sample or by dilution with natural carbon or carbon dioxide during the transfer process. This article discusses the possibility of carbon-13 isotope propagation directly in these compounds, both completely modified and modified with individual carbon centers. The literature provides information on determining carbon-13 substance in organic compounds, both with a general approach and for individual compounds [2] [3].展开更多
基金supported by the“Fundamental Research Funds for the Central Universities”(Nos.21620318 and 2019QNGG22)the“Guangdong Basic and Applied Basic Research Fund”(No.2021A1515012023)“the Open Fund of Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications”(No.2020B121201005).
文摘A NHC-catalyzed hypervalent iodine reagents and transition-metal free redox-neutral dearomatization of phenols is reported.This protocol provides an efficient access for highly congested quaternatry carbon centers construction.It also features operationally simplicity,mild reaction conditions and good functional group tolerance.Moreover,the reported procedure can be easily emplified to 1 g scale.Mechanism study reveals the dearomative transformation possibly undergoes a single electron transfer process with NHC radical cation as a reactive intermediate.
基金We are grateful for financial support from the National Natural Science Foundation of China(No.21762005)Natural Science Foundation of Guangxi Province(No.2021GXNSFDA075005).
文摘An intriguing Brønsted acid-catalyzed 1,6-hydrophosphination of in situ generated propargylic para-quinone methides(p-QMs)and aza-para-quinone methides(aza-p-QMs)with H-phosphorus oxides via dehydration/1,6-addition under ultrasonic irradiation is described.This methodology provides a rapid and green approach for the construction of diarylmethyl phosphorus oxides bearing phosphorus-substituted quaternary carbon centers in high yields(up to 98%yield)within merely 5min.This environmentally benign protocol represents a unique example of 1,6-conjugate additions of propargylic p-QMs and aza-p-QMs for site-selective C-P bond formation in an operationally simple and atom-economical manner.The use of readily available Brønsted acid catalyst,operationally simplicity,high yields,and high atom economy make this protocol very facile,practical,easily scaled-up and environmentally friendly.
文摘Tartaric acid, oxalic acid, glucose, and fructose are highly important compounds. A comprehensive study of these substances is fascinating from a scientific perspective. They are key components found in wine, vegetables, and fruits. Understanding the isotopic compositions in organic compounds is crucial for comprehending various biochemical processes and the nature of substances present in different natural products. Tartaric acid, oxalic acid, glucose, and fructose are widely distributed compounds, including in vegetables and fruits. Tartaric acid plays a significant role in determining the quality and taste properties of wine, while oxalic acid is also prevalent but holds great interest for further research, especially in terms of carbon isotopic composition. We can unveil the mechanisms of processes that were previously impossible to study. Glucose and fructose are the most common monosaccharides in the hexose group, and both are found in fruits, with sweeter fruits containing higher amounts of these substances. In addition to fruits, wheat, barley, rye, onions, garlic, lentils, peppers, dried fruits, beans, broccoli, cabbage, tomatoes, and other foods are also rich sources of fructose and glucose. To determine the mass fraction of the carbon-13 isotope in these compounds, it is important to study their changes during natural synthesis. These compounds can be modified with a carbon center. According to the existing isotopic analysis method, these compounds are converted into carbon oxide or dioxide [1]. At this point, the average carbon content in the given compound is determined, but information about isotope-modified centers is lost. Dilution may occur through the transfer of other carbon-containing organic compounds in the sample or by dilution with natural carbon or carbon dioxide during the transfer process. This article discusses the possibility of carbon-13 isotope propagation directly in these compounds, both completely modified and modified with individual carbon centers. The literature provides information on determining carbon-13 substance in organic compounds, both with a general approach and for individual compounds [2] [3].
