Article
Chemistry, Multidisciplinary
Huiling Shao, Suman Chakrabarty, Xiaotian Qi, James M. Takacs, Peng Liu
Summary: The use of conformationally flexible TADDOL-derived ligands in Rh-catalyzed asymmetric hydroboration reactions was found to enhance reactivity and selectivity by promoting asymmetric construction of the carbon center and controlling ligand-substrate interactions in different elementary steps. The flexibility of the ligand backbone allowed for distinct steric environments that facilitated the favorable reaction pathways.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Amit Kumar Simlandy, Warabhorn Rodphon, Turki M. Alturaifi, Binh Khanh Mai, Hui-Qi Ni, John A. Gurak Jr, Peng Liu, Keary M. Engle
Summary: A redox-neutral catalytic coupling of nitroalkanes and unactivated alkenes is reported in this study, which proceeds by a directed carbopalladation mechanism. The combination of PdI2 as the precatalyst and HFIP solvent enables the reaction uniquely. Structurally complex nitroalkane products, including nitro-containing carbo- and heterocycles, can be prepared under convenient conditions without the use of toxic or corrosive reagents. The reaction mechanism is examined through deuterium labeling experiments and isolation of a catalytically relevant intermediate. Different catalytic activation modes are utilized to demonstrate orthogonal methods for site-selective functionalization of a polyfunctional nitroalkyl ketone. Density functional theory (DFT) calculations reveal that the carbopalladation transition state is stabilized by a Na·I interaction and H·I hydrogen bond with HFIP.
Article
Chemistry, Physical
Amit Kumar Simlandy, Warabhorn Rodphon, Turki M. Alturaifi, Binh Khanh Mai, Hui-Qi Ni, John A. Gurak, Peng Liu, Keary M. Engle
Summary: We report a redox-neutral catalytic coupling of nitroalkanes and unactivated alkenes that proceeds by a directed carbopalladation mechanism. The reaction is enabled by the combination of PdI2 as the precatalyst and HFIP solvent. Complex nitroalkane products, including nitro-containing carbo- and heterocycles, can be prepared under convenient conditions without the need for toxic or corrosive reagents.
Article
Chemistry, Multidisciplinary
Mingyu Liu, Juntao Sun, Tao Zhang, Yi Ding, Ye-Qiang Han, Raul Martin-Montero, Yu Lan, Bing-Feng Shi, Keary M. Engle
Summary: This article describes a catalytic 1,2-oxyhalogenation method that converts non-conjugated internal alkynes into tetrasubstituted alkenes with high selectivity. The selectivity depends on the formation of a six-membered palladacycle intermediate in the oxypalladation step and the identity of the halide anion.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Organic
Dezheng Xie, Ziyi Chen, Chun-Jiang Wang, Xiu-Qin Dong
Summary: Phosphonates and derivatives with an α-chiral center are important compounds found in natural products, pharmaceuticals, and agrochemicals. The synthesis of these compounds has been the focus of recent research, with advancements in asymmetric catalysis such as hydrogenation, addition reactions, and nucleophilic additions to α,β-unsaturated phosphonates. The continuous development of enantioselective catalytic methods and the future applications of these compounds are also discussed.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Multidisciplinary
Jun Chen, Zhan Shi, Chunyu Li, Ping Lu
Summary: A sequential enantioselective reduction/C-H functionalization method was developed for installing contiguous stereogenic carbon centers of benzocyclobutenols and cyclobutanols. This strategy involves practical enantioselective reduction of a ketone and diastereospecific iridium-catalyzed C-H silylation, with further transformations explored, including controllable regioselective ring-opening reactions. Additionally, this strategy has been utilized for the synthesis of three natural products.
Article
Chemistry, Organic
Liyao Zeng, Menglong Zhao, Bijin Lin, Jingyuan Song, James H. R. Tucker, Jialin Wen, Xumu Zhang
Summary: A new cobalt catalytic system for asymmetric hydrogenation of ketones was developed using ferrocene-based secondary phosphine oxide ligands. The coordination pattern of cobalt with the ligands was confirmed by X-ray diffraction. The cobalt complexes exhibited high reactivities (up to 99% yield) and good to excellent enantioselectivities (up to 92% ee) in the hydrogenation of ortho-substituted diaryl ketones. Moreover, the diferrocenyl cobalt complex showed intriguing UV-vis absorption and electrochemical properties.
Article
Chemistry, Multidisciplinary
Xin Gao, Joshua R. Turek-Herman, Young Joo Choi, Ryan D. Cohen, Todd K. Hyster
Summary: This study demonstrates that engineered flavin-dependent 'ene'-reductases (EREDs) can catalyze radical additions into oximes with high stereoselectivity to prepare alpha-tertiary amines, which are common in pharmaceutical molecules. Two evolved EREDs were competent catalysts for this transformation, and mechanistic studies revealed the role of oximes in the enzyme templated charge-transfer complex. The products can be further derivatized for the synthesis of various motifs, showcasing the versatility of ERED photoenzymatic catalysis in organic synthesis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
James D. Grayson, Francesca M. Dennis, Craig C. Robertson, Benjamin M. Partridge
Summary: In this study, a Chan-Lam coupling reaction of benzylic and allylic boronic esters with primary and secondary anilines was reported to form valuable alkyl amine products. Both secondary and tertiary boronic esters were used as coupling partners, resulting in selective mono-alkylation of the aniline. This rare example demonstrated a transition-metal-mediated transformation of a tertiary alkylboron reagent, with initial investigation suggesting a single-electron transmetalation mechanism from B to Cu.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Rebecca A. Kehner, Ge Zhang, Liela Bayeh-Romero
Summary: A mild and catalytic method for the semireduction of both secondary and tertiary amides via zirconocene hydride catalysis is reported. The reduction of secondary amides gives a diverse array of imines in up to 94% yield with excellent chemoselectivity using just 5 mol % of Cp2ZrCl2, without the need for glovebox handling. Furthermore, a novel reductive transamination of tertiary amides is achieved in the presence of a primary amine at room temperature, providing access to an expanded assortment of imines in up to 98% yield. Through slight procedural tuning, the single-flask conversion of amides to imines, aldehydes, amines or enamines is feasible, including multicomponent syntheses.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Ahreum Kim, Chanhee Lee, Jayoung Song, Sang Kook Lee, Yongseok Kwon
Summary: In this study, a flexible platform for chiral phosphoric acid-catalyzed atroposelective dynamic kinetic resolution was reported using o-amidobiaryl as the substrate. The platform demonstrated excellent enantioselectivity control over substrates with different aromatic ring positions when reacted with ketomalonate in the presence of chiral phosphoric acid. Computational investigation highlighted the importance of the NH group in determining the enantioselectivity. Furthermore, the scaffold showed good efficacy in antiproliferative effects.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Can-Can Bao, Yan-Long Luo, Hui-Zhen Du, Bing-Tao Guan
Summary: The study reported a method using LDA-promoted benzylic aroylation of toluenes with unactivated tertiary benzamides, providing an efficient synthesis of various aryl benzyl ketones.
SCIENCE CHINA-CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yue Jin, Yashi Zou, Yanhua Hu, Yunxi Han, Zhenfeng Zhang, Wanbin Zhang
Summary: A highly efficient azole-directed cobalt-catalyzed asymmetric hydrogenation of alkenes has been developed. This method allows for the synthesis of chiral pyrazole compounds with quantitative yields and excellent enantioselectivities (up to 99% ee) under mild conditions. The reaction can be conducted on a gram scale with high turnover numbers (up to 2000 TON) and has demonstrated several useful applications including the introduction of beta-chirality to drug intermediates containing an azole ring.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Organic
Chuan-Zhi Yao, Xue-Qin Tu, Hua-Jie Jiang, Qiankun Li, Jie Yu
Summary: This paper provides a comprehensive overview of the recent advances in catalytic asymmetric intra- and intermolecular haloamination and haloetherification of olefins, discussing the scopes and strategies of these new methods developed since 2015.
TETRAHEDRON LETTERS
(2023)
Article
Chemistry, Physical
Taeho Kang, Jose Manuel Gonzalez, Zi-Qi Li, Klement Foo, Peter T. W. Cheng, Keary M. Engle
Summary: This study presents a versatile method for accessing differentially substituted 1,3- and 1,4-diamines through nickel-catalyzed three-component 1,2-carboamination of alkenyl amines. The reaction is efficient, regioselective, and compatible with a wide range of coupling partners, all performed at room temperature.
Article
Chemistry, Organic
Xiang Wang, Anil Guram, Emilio Bunel, Guo-Qiang Cao, Jennifer R. Allen, Margaret M. Faul
JOURNAL OF ORGANIC CHEMISTRY
(2008)
Article
Chemistry, Organic
Seb Caille, Sheng Cui, Tsang-Lin Hwang, Xiang Wang, Margaret M. Faul
JOURNAL OF ORGANIC CHEMISTRY
(2009)
Article
Chemistry, Organic
Xiang Wang, Anil Guram, Seb Caille, Jack Hu, J. P. Preston, Michael Ronk, Shawn Walker
Article
Chemistry, Organic
Anil S. Guram, Xiang Wang, Emilio E. Bunel, Margaret M. Faul, Robert D. Larsen, Michael J. Martinelli
JOURNAL OF ORGANIC CHEMISTRY
(2007)
Article
Chemistry, Organic
Xiang Wang, Denis V. Gribkov, Dalibor Sames
JOURNAL OF ORGANIC CHEMISTRY
(2007)
Article
Chemistry, Multidisciplinary
X Wang, BS Lane, D Sames
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2005)
Article
Chemistry, Multidisciplinary
XQ Han, X Wang, T Pei, RA Widenhoefer
CHEMISTRY-A EUROPEAN JOURNAL
(2004)
Article
Chemistry, Multidisciplinary
C Liu, X Wang, T Pei, RA Widenhoefer
CHEMISTRY-A EUROPEAN JOURNAL
(2004)
Article
Chemistry, Inorganic & Nuclear
X Wang, RA Widenhoefer
Article
Chemistry, Multidisciplinary
C Liu, XQ Han, X Wang, RA Widenhoefer
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2004)
Article
Chemistry, Multidisciplinary
X Wang, RA Widenhoefer
CHEMICAL COMMUNICATIONS
(2004)
Article
Chemistry, Organic
X Wang, T Pei, XQ Han, RA Widenhoefer
Article
Chemistry, Multidisciplinary
T Pei, X Wang, FA Widenhoefer
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2003)
Article
Chemistry, Multidisciplinary
Zhibin Zhang, Xiang Wang, Ross A. Widenhoefer
CHEMICAL COMMUNICATIONS
(2006)