Article
Chemistry, Organic
Yakun Wang, Shuaifei Wang, Peiyong Qiu, Lizhen Fang, Ke Wang, Yawei Zhang, Conghui Zhang, Ting Zhao
Summary: An efficient and enantioselective alpha-electrophilic difluoromethylation of beta-keto esters has been achieved by phase-transfer catalysis, providing good enantioselectivities and yields with high C/O regioselectivities. The C/O selectivity of beta-keto esters can be easily reversed and controlled, offering a novel and efficient way for introducing chiral C-CF2H groups.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Georgia R. Harris, Aaron D. Trowbridge, Matthew J. Gaunt
Summary: We report the stereocontrolled addition of alpha-amino radicals to alkenes through visible-light-mediated photo-redox-catalysis, generating enantioenriched alpha-trialkyl-alpha- tertiary amines. This process utilizes a commercially available phenylglycinol derivative as a source of nitrogen and chiral information. DFT studies confirm the role of an intramolecular H-bond in rigidifying the transition state of the enantiodetermining step.
Article
Chemistry, Multidisciplinary
Mao Cai, Kaini Xu, Yuze Li, Zongxiu Nie, Long Zhang, Sanzhong Luo
Summary: The study presents a cooperative primary amine and ketone dual catalytic approach for the asymmetric alpha-hydroxylation of beta-ketocarbonyls with H2O2, achieving excellent yield and enantioselectivity. This cooperative amine/ketone catalytic approach provides a new strategy for the catalytic activation of H2O2 and expands the domain of typical amine and carbonyl catalysis to include this challenging transformation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Yu-Bin Wang, Fei Chen, Min Li, Qingqing Bu, Zhihong Du, Jichang Liu, Bin Dai, Ning Liu
Summary: Visible light-promoted strategies were developed for the synthesis of gem-dihaloenones using alkynes and polyhalomethanes as the starting materials. The methods produce a broad range of gem-dibromoenones and gem-dichloroenones without using photocatalysts or additives, such as bases and oxidants. This is the first example of a photocatalyst-free strategy for the photo-promoted synthesis of gem-dihaloenones. These protocols were compatible with various terminal and internal alkynes and were effective in gram-scale experiments.
Article
Chemistry, Organic
An-Jing Wang, Chun-Yan She, Yu-Die Zhang, Li-Han Zhao, Wen-Ming Shu, Wei-Chu Yu
Summary: A copper(II)-promoted denitrogenation/oxidation reaction was developed to prepare primary alpha-ketoamides using alpha-azido ketones as substrate and TEMPO as oxidant. In this reaction, alpha-azido ketones were denitrogenated in situ to form an imino ketone intermediate, which then underwent radical addition and radical migration to yield alpha-ketoamides. The imino ketone intermediate plays a crucial role in this reaction.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Review
Chemistry, Multidisciplinary
Renyu Guo, M. Kevin Brown
Summary: In this study, Lewis acid-promoted [2+2] cycloaddition reactions were used to synthesize various cyclobutanes with stereochemical control. Additionally, catalytic enantioselective [2+2] cycloadditions were achieved using chiral catalysts. These methods have proven to be instrumental in the synthesis of natural products.
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Chemistry, Organic
Yanfang Han, Long Zhang, Sanzhong Luo
Summary: A highly diastereo- and enantioselective retro-Claisen reaction has been developed using chiral primary amine catalysis. This reaction enables efficient synthesis of chiral beta,beta-diaryl-alpha-branched ketones with excellent stereoselectivities. The reaction proceeds through a tandem sequence involving benzylic C-C bond formation, C-C bond cleavage, and stereospecific enamine protonation. The use of o-quinone methides as diaryl precursors allows for a broad substrate scope, mild reaction conditions, and a high degree of stereocontrol.
Article
Chemistry, Multidisciplinary
Andrej Sterman, Izidor Sosic, Zdenko Casar
Summary: This work describes the preparation and application of primary trifluoroborate-iminiums (pTIMs) as a new and valuable class of organoboron derivatives. Highly enantioselective hydrogenation reactions were used to obtain chiral primary trifluoroborate-ammoniums (pTAMs). A facile conversion method using hexamethyldisiloxane/aqueous HCl was then used to synthesize diverse chiral alpha-aminoboronic acids from chiral pTAMs. The synthesis of optically pure anti-cancer drugs bortezomib and ixazomib demonstrated the practicality of this method.
Article
Chemistry, Multidisciplinary
Yang Gao, Phil S. Baran
Summary: A new approach to the enantiocontrolled synthesis of alpha-amino ketone derivatives is presented using a decarboxylative acylation strategy. This method yields the desired alpha-amido ketones with good yield and high enantioselectivity when an acyl chloride and an alpha-amido-containing redox-active ester are exposed to a nickel catalyst, chiral ligand, and metal reductant. The reaction has wide substrate scope, scalability, and simplifies the synthesis of known structures.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Mao Cai, Kaini Xu, Haoyuan Jia, Long Zhang, Xueling Mi, Sanzhong Luo
Summary: Highly effective and stereoselective enamine-singletoxygen coupling was achieved by synergistic chiral primary amine and photocatalysis in hexafluoroisopropanol. The current enamine catalysis enables alpha-hydroxylation of beta-ketocarbonyls with good yields and high enantioselectivity across a broad range of substrates. Mechanistic studies revealed a direct participation of solvents in the critical enamine coupling step, and a solvent-O-1(2) H-bonding mode was invoked to account for the dramatic solvent effect.
Review
Chemistry, Organic
Chao-Jiu Long, Yan-Hong He, Zhi Guan
Summary: This minireview highlights the significant advances in asymmetric oxidative Mannich reactions using photoredox or anodic-oxidation strategies. It discusses the synthesis of chiral beta-amino carbonyl compounds and provides insights into the future development of this field.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Organic
Jie Zhang, Yaning Wang, Chang You, Mingying Shi, Xueling Mi, Sanzhong Luo
Summary: We report a synergetic chiral primary amine and rhodium catalysis for the asymmetric coupling of beta-ketocarbonyls and alkynes. This method enables the synthesis of linear allylation products with all-carbon quaternary centers in high regio- and enantioselectivities.
Article
Chemistry, Organic
Hongyan Zhou, Ganggang Wang, Cunhui Wang, Jingya Yang
Summary: In this study, a visible-light-promoted aerobic oxyphosphorylation of alpha-diazoesters and H-phosphine oxides has been developed. The reaction proceeds smoothly at room temperature using air as the oxygen source and blue-light irradiation. Preliminary mechanistic studies indicate the involvement of a light-triggered radical process. This strategy reveals the previously unknown reactivity of diazo compounds with H-phosphine oxides and has potential value in synthetic applications.
Article
Chemistry, Physical
Pradip Ramdas Thorve, Biplab Maji
Summary: A bioinspired catalytic system was developed for the one-pot cascade oxidation of a native primary amine and an in situ generated non-native secondary amine, yielding quinazolin-4(3H)-ones commonly found in pharmaceuticals and bioactive compounds in high yields. The detailed kinetic and mechanistic study provided insights into the role of the catalyst in the multi-step oxidative cascade reaction.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Organic
Santanu Mondal, Ravindra D. Aher, Venkati Bethi, Yu-Ju Lin, Tohru Taniguchi, Kenji Monde, Fujie Tanaka
Summary: This study reports amine-based catalyst systems for the enantioselective Mannich reactions of pyruvates as nucleophiles. The reactions of pyruvates and cyclic sulfonylimines yielded the desired Mannich products, including those with tetrasubstituted carbon centers, in high yields and enantioselectivities. The choice of acid in the amine-based catalyst system played a key role in the formation of Mannich products with high enantioselectivities.
Article
Chemistry, Organic
Alessia Ciogli, Donatella Capitani, Nicola Di Iorio, Simone Crotti, Giorgio Bencivenni, Maria Pia Donzello, Claudio Villani
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2019)
Article
Chemistry, Organic
Simone Crotti, Nicola Di Iorio, Chiara Artusi, Andrea Mazzanti, Paolo Righi, Giorgio Bencivenni
Article
Chemistry, Organic
Michel Chiarucci, Andrea Mazzanti, Paolo Righi, Giorgio Bencivenni, Michele Mancinelli
Summary: A series of 1,8-bis(1-naphthyl)-naphthalenes with different substituents have been synthesized to investigate noncovalent interactions between stacked arenes. DFT calculations, NMR, and ECD experiments were used to determine the best geometries and understand the role of dispersive and electrostatic contributions. The study revealed that electrostatic contributions greatly influence the interaction energy of the two naphthyl rings, while dispersive forces play a minor role in determining the parallel displaced geometry.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Nicolo Tampellini, Paolo Righi, Giorgio Bencivenni
Summary: A computational study using density functional theory was conducted to understand the mechanism of atroposelective desymmetrization of N-(2-t-butylaryl)maleimide catalyzed by 9-amino(9-deoxy) epi-quinine. The results showed that the atroposelectivity was achieved through steric and dispersion interactions of the catalyst. The crucial role of N-Boc-L-Ph-glycine was identified in forming a closed transition-state geometry and activating the reaction partners.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Antonia Iazzetti, Giulia Mazzoccanti, Giorgio Bencivenni, Paolo Righi, Andrea Calcaterra, Claudio Villani, Alessia Ciogli
Summary: The field of organocatalysis is expanding rapidly, with a focus on understanding mechanisms of reaction and catalytic processes. A thorough study using ESI-MS spectrometry of amino-organocatalyzed reactions has provided insights into the complex pathways involved.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Chiara Portolani, Giovanni Centonze, Sara Luciani, Andrea Pellegrini, Paolo Righi, Andrea Mazzanti, Alessia Ciogli, Andrea Sorato, Giorgio Bencivenni
Summary: The first catalytic enantioselective and diastereoselective synthesis of atropisomeric hydrazides was achieved using a sequential catalysis protocol, providing a stereodivergent approach to enantioenriched atropisomeric hydrazides. The resulting axially chiral hydrazides were obtained directly from commercially available reagents in high yields and with good stereocontrol, demonstrating the effectiveness of this strategy.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Multidisciplinary
Chiara Portolani, Giovanni Centonze, Paolo Righi, Giorgio Bencivenni
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Chemistry, Physical
Jacopo De Maron, Tommaso Tabanelli, Francesca Ospitali, Carlos Lopez Cruz, Paolo Righi, Fabrizio Cavani
Summary: For the first time, the continuous-flow, gas-phase oxidative dehydrogenation (ODH) of an actual mixture of decen-1-ol isomers (Isorosalva alcohol) towards the corresponding mixture of aldehydes (Costenal analogues, valuable ingredients in perfumes formulation) was achieved over noble metal-free catalysts. The optimized reaction conditions over a copper ferrite (Cu/Fe/O) and the characterization of the catalytic material revealed the important role of well dispersed copper oxide over a Fe-enriched spinel in promoting the selective ODH of Isorosalva alcohol. The high dispersion of Cu over the support and the cooperative effect between Cu and Fe species were identified as the main factors for the superior catalytic activity and selectivity of CuO/gamma-Fe2O3.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Review
Chemistry, Multidisciplinary
Giovanni Centonze, Chiara Portolani, Paolo Righi, Giorgio Bencivenni
Summary: Axially chiral compounds, once viewed as merely a laboratory curiosity, have gained recognition in the past two decades for their significant role in medicinal, biological, and material chemistry. The asymmetric synthesis of atropisomers, particularly N-N atropisomers, has become a rapidly expanding field with new challenges and frontiers. This review highlights recent advances and breakthroughs in the enantioselective synthesis of N-N atropisomers, showcasing the strategies and frameworks involved.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)