Article
Chemistry, Organic
Siming Jia, Mengmeng Ma, Er-Qing Li, Zheng Duan, Francis Mathey
Summary: Two novel diastereoisomeric P-chirogenic phosphine catalysts, JiaPhos, were successfully synthesized from inexpensive starting materials in five chemical operations on a 4.16g scale. These catalysts demonstrated excellent performance in enantioselective (4 + 2) annulations, providing a diverse range of 3,3'-spirocyclic oxindoles with high efficiency and enantioselectivity.
Article
Chemistry, Applied
You-Cai Wu, Bao-Dong Cui, Yan Long, Wen-Yong Han, Nan-Wei Wan, Wei-Cheng Yuan, Yong-Zheng Chen
Summary: The study demonstrates an asymmetric (4+1) annulation catalyzed by a chiral phosphoric acid, leading to the synthesis of a range of spiro[dihydrobenzofuran-2,3 '-oxindoles/2,4 '-oxisoquinoline] derivatives with excellent stereocontrol. The protocol showcases metal-free participation with heterocyclic diazo compounds as direct nucleophiles, offering a straightforward and efficient process for accessing structurally-diverse spiro-heterocyclic compounds.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Ze-ren Yang, Min Shi
Summary: A new method has been developed for the synthesis of spiro[azepane-4,3'-indol]-2'(1'H)-ones with yields of up to 96%, using oxotryptamines as dual-nucleophilic reagents to react with allenoates in the presence of cesium carbonate under mild conditions. A plausible reaction mechanism is proposed based on previous works and a deprotonation-tracing experiment.
Article
Chemistry, Organic
Ke Li, Zhenjie Gan, Er-Qing Li, Zheng Duan
Summary: A novel phosphine-catalyzed (4 + 2) cyclization reaction has been reported for the generation of functionalized dihydropyran skeletons from electron-deficient conjugated dienes and enones. Mechanistic investigation reveals the formation of a new phosphonium zwitterion, which undergoes consecutive reactions. An asymmetric variant has also been developed through efficient and economical chiral phosphine catalysis.
Article
Chemistry, Organic
Jie Tang, Zhen-Hui Yan, Gu Zhan, Qian-Qian Yang, Ying-Ying Cheng, Xiang Li, Wei Huang
Summary: This study discloses for the first time the visible-light-mediated sequential Wolff rearrangement and Staudinger cycloaddition, which utilize in situ generated ketenes and pyrazolone ketimines to assemble valuable spiro-pyrazolone-beta-lactams. This powerful approach exhibits high yield, good substrate tolerance, and gram-scale capacity, providing straightforward access to multisubstituted pyrazole-morpholine skeletons.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Yan Long, Yun Wang, Yue-You Chen, Wen-Yong Han, Nan-Wei Wan, Wei-Cheng Yuan, Yong-Zheng Chen, Bao-Dong Cui
Summary: This article describes an inexpensive copper-catalyzed sequential reaction process for synthesizing structurally diverse spiro-dihydropmolo[1,2-a]quinoxaline derivatives. The significance of this method is highlighted by its ability to convert synthetic compounds into potentially bioactive molecules.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Hanyuan Li, Zhengjie He
Summary: This study reports a chiral phosphine-catalyzed asymmetric annulation reaction, which efficiently synthesizes enantio-enriched polysubstituted cyclopentenes with high stereoselectivity.
TETRAHEDRON LETTERS
(2021)
Article
Chemistry, Organic
Dongqiu Li, Fang Cheng, Yuhai Tang, Jing Li, Yang Li, Jiao Jiao, Silong Xu
Summary: The method described involves a phosphine-catalyzed internal redox [4 + 2] annulation of 1,4-enynoates with electron-deficient alkenes, resulting in the efficient synthesis of highly functionalized cyclohexenes with exclusive regioselectivity and high diastereoselectivity under mild conditions.
Article
Chemistry, Organic
Hui Xu, Ran Hong, Ming-Yue Weng, Rong-Lu Huang, Guan-Wu Wang, Ze Zhang
Summary: By utilizing different catalysts under different conditions, it is possible to selectively synthesize structurally diverse 4,5'- and 4,4'-imidazolinyl spiropyrazolones, leading to the development of a powerful metal-free method.
Article
Chemistry, Organic
Sachin Chauhan, Shubham Debnath, K. C. Kumara Swamy
Summary: This study reports the Lewis base dependent (3 + 3) annulation of delta-acetoxy allenoates with benzofuranone, pyrazolone, and Boc-protected oxindole. In the presence of catalytic DBU, oxindole, benzofuranone, and pyrazolone undergo (3 + 3) annulation with delta-acetoxy allenoates via 6-exo-dig cyclization at room temperature (25 degrees C) to afford fused pyran scaffolds. On the other hand, by employing catalytic DMAP, the reaction between N-Boc-oxindole and delta-acetoxy allenoates goes through 6-endo-dig cyclization, leading to distinct dihydropyrans that contain an exocyclic double bond; similar products were also obtained by using benzofuranone and pyrazolone.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Min Gao, Yanshu Luo, Qianlan Xu, Yukun Zhao, Xiangnan Gong, Yuanzhi Xia, Lin Hu
Summary: The research achieved a unified catalytic asymmetric (N+1) (N=4, 5) annulation reaction of oxindoles with bifunctional peroxides using a chiral phase-transfer catalyst (PTC). This method provides a distinct way to access valuable chiral spirooxindole-tetrahydrofurans and -tetrahydropyrans with good yields and high enantioselectivities under mild conditions. The DFT calculations were performed to rationalize the high enantioselectivity observed in the reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Jiaming Zhang, Jing Luo, Xue Li, Qiaoyu Zhang, Zhoujie Wu, Yu Lan, Donghui Wei
Summary: A computational study was conducted to investigate the mechanisms of beta-isocinchonine-catalyzed asymmetric C(sp(2))-H allylation of trisubstituted allenoates using Morita-Baylis-Hillman (MBH) carbonates for the synthesis of axially chiral tetrasubstituted allenoates. The results suggest that the most energetically favorable pathway involves several steps, including nucleophilic attack, dissociation of BocO(-), C-C bond formation, and catalyst regeneration. The study also highlights the importance of C-H···O and C-H···π interactions in controlling axial and central chirality.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Dongqiu Li, Fang Cheng, Yuhai Tang, Jing Li, Yang Li, Jiao Jiao, Silong Xu
Summary: In this study, we describe a DABCO-catalyzed [4 + 2] annulation reaction between 5-methylenehex-2-ynedioates and electron-deficient olefins, which leads to the formation of functionalized cyclohexadienes in good yields under mild reaction conditions. The incorporation of the beta- and epsilon-carbons of the substrates for C-C bond formation represents a novel reactivity different from previous reports. It is believed that the annulation proceeds through a domino cyclization initiated by a cross Rauhut-Currier reaction.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Yang An, Xiao-Yan Zhang, Ya-Nan Ding, Yuke Li, Xue-Yuan Liu, Yong-Min Liang
Summary: This study synthesized ferrocenes with planar chirality using palladium/chiral norbornene cooperative catalysis and axial-to-planar diastereoinduction. The chiral norbornene was used to control the aromatic axial chirality and induce the planar chirality of ferrocene through C(sp2)-H activation.
Article
Chemistry, Organic
Rajshekhar A. Unhale, Milon M. Sadhu, Vinod K. Singh
Summary: A novel organocatalytic asymmetric formal [3 + 2] cycloaddition has been developed for the synthesis of biologically relevant chiral spiroisoindolinone-indolines with excellent yields and enantioselectivity under mild conditions.
Article
Chemistry, Organic
Jacek Kwiatkowski, Yixin Lu
ORGANIC & BIOMOLECULAR CHEMISTRY
(2015)
Article
Energy & Fuels
Yong Ren Tan, Maria L. Botero, Yuan Sheng, Jochen A. H. Dreyer, Rong Xu, Wenming Yang, Markus Kraft
Article
Chemistry, Medicinal
Jacek Kwiatkowski, Boping Liu, Doris Hui Ying Tee, Guoying Chen, Nur Huda Binte Ahmad, Yun Xuan Wong, Zhi Ying Poh, Shi Hua Ang, Eldwin Sum Wai Tan, Esther H. Q. Ong, Nurul Dinie, Anders Poulsen, Vishal Pendharkar, Kanda Sangthongpitag, May Ann Lee, Sugunavathi Sepramaniam, Soo Yei Ho, Joseph Cherian, Jeffrey Hill, Thomas H. Keller, Alvin W. Hung
JOURNAL OF MEDICINAL CHEMISTRY
(2018)
Article
Chemistry, Multidisciplinary
Jacek Kwiatkowski, Yixin Lu
CHEMICAL COMMUNICATIONS
(2014)
Article
Chemistry, Organic
Jacek Kwiatkowski, Yixin Lu
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2015)
Article
Chemistry, Organic
Jacek Kwiatkowski, Yixin Lu
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2014)
Article
Chemistry, Medicinal
Jacek Kwiatkowski, Nithya Baburajendran, Anders Poulsen, Boping Liu, Doris Hui Ying Tee, Yun Xuan Wong, Zhi Ying Poh, Esther H. Q. ong, Nurul Dinie, Joseph Cherian, Anna Elisabet Jansson, Jeffrey Hill, Thomas H. Keller, Alvin W. Hung
ACS MEDICINAL CHEMISTRY LETTERS
(2019)
Article
Chemistry, Medicinal
Jacek Kwiatkowski, Boping Liu, Shermaine Pang, Nur Huda Binte Ahmad, Gang Wang, Anders Poulsen, Haiyan Yang, Yong Rui Poh, Doris Hui Ying Tee, Esther Ong, Priya Retna, Nurul Dinie, Perlyn Kwek, John Liang Kuan Wee, Vithya Manoharan, Choon Bing Low, Peck Gee Seah, Vishal Pendharkar, Kanda Sangthongpitag, Joma Joy, Nithya Baburajendran, Anna Elisabet Jansson, Kassoum Nacro, Jeffrey Hill, Thomas H. Keller, Alvin W. Hung
JOURNAL OF MEDICINAL CHEMISTRY
(2020)
Article
Energy & Fuels
Yong Ren Tan, Maurin Salamanca, Laura Pascazio, Jethro Akroyd, Markus Kraft
Summary: This study investigates the impact of PODE3 on soot formation in ethylene/PODE3 flames, finding that at low blending levels, PODE3 may actually increase soot formation. Results suggest that sufficient amounts of PODE3 can reduce soot formation, specifically in C2 chemistry systems.
Article
Thermodynamics
Yong Ren Tan, Maurin Salamanca, Jethro Akroyd, Markus Kraft
Summary: This study investigates the sooting behavior of fuel mixtures by blending four oxygenated fuels with Jet A2 aviation fuel. The addition of oxygenated fuels significantly reduces the sooting tendency, especially at low blend strengths. The volume fraction and particle size distribution of soot are correlated with the oxygen extended sooting index.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Yong Ren Tan, Maurin Salamanca, Jiaru Bai, Jethro Akroyd, Markus Kraft
Summary: This study investigates the impact of the structure of three C3 oxygenated fuels on soot formation in laminar coflow diffusion flames when blended with ethylene. It was found that different oxygenated fuels have different effects on the soot volume fraction (f(v)), with IPA causing a significant increase, while DMM and DMC showed initial increases followed by decreases in f(v) as the proportion of oxygenated fuel increased.
COMBUSTION AND FLAME
(2021)
Article
Energy & Fuels
Qiren Zhu, Yichen Zong, Yong Ren Tan, Jieyao Lyu, Wenbin Yu, Wenming Yang, Markus Kraft
Summary: This study investigates the effects of diesel/n-butanol blends on particulate matter (PM) emissions in a common-rail diesel engine. The results show that the addition of n-butanol can improve fuel and oxidizer mixing, resulting in lower chamber temperature and reduced emissions of HC, NOx, and PM. The study also finds that n-butanol increases the oxidative reactivity of soot particles and shorter combustion duration leads to higher disorder level of particles.
Article
Thermodynamics
Yong Ren Tan, Yichen Zong, Maurin Salamanca, Jacob W. Martin, Jochen A. H. Dreyer, Jethro Akroyd, Wenming Yang, Markus Kraft
Summary: A novel modified coflow burner was developed to inject charge from a non-thermal plasma into helium-diluted ethylene flames. Different frequencies of the high voltage signal were used to control the ion concentration injected into the flames. Optical emission spectroscopy and other measurements were conducted to study the effect of charge injection on soot reduction in the flames. The results showed that the system is a promising candidate for studying the charge effect from non-thermal plasma on soot formation in laminar coflow diffusion flames.
COMBUSTION SCIENCE AND TECHNOLOGY
(2023)
Article
Energy & Fuels
Yong Ren Tan, Qiren Zhu, Yichen Zong, Jiawei Lai, Maurin Salamanca, Jethro Akroyd, Wenming Yang, Markus Kraft
Summary: This study investigates the effects of oxygenated fuels on soot produced by a compression ignition engine. The addition of ethanol and polyoxymethylene dimethyl ether 1 (PODE1) improves brake thermal efficiency (BTE), reduces soot accumulation, and promotes organic carbon formation. However, the addition of dimethyl carbonate (DMC) decreases BTE.
