Article
Chemistry, Organic
Perla Bharath Kumar, Chittala Emmaniel Raju, Patel Hinal Chandubhai, Balasubramanian Sridhar, Galla V. Karunakar
Summary: Molecules obtained from nature have various biological applications in medicinal chemistry, agrochemicals, and material sciences. Oxygen-containing molecules such as chromenes and benzochromenes are found to have potential biological applications.
Article
Chemistry, Multidisciplinary
Andrea Cataffo, Miguel Pena-Lopez, Riccardo Pedrazzani, Antonio M. Echavarren
Summary: This study presents two classes of stereoselective cyclizations using a chiral auxiliary approach. The first class involves the stereoselective cascade cyclization of 1,5-enynes using Oppolzer camphorsultam as chiral auxiliary, leading to the synthesis of enantioenriched spirocyclic ketones. The second class focuses on the stereoselective alkoxycyclization of 1,6-enynes mediated by Evans-type oxazolidinone, resulting in the formation of enantioenriched beta-tetralones after removal of the auxiliary.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Chunxiang Pan, Gaowei Wang, Hengyuan Zhao, Jianxiao Ni, Ruifeng Fan, Yongyun Zhou, Yuanbin Zhu, Shiyuan Wu, Baomin Fan
Summary: An efficient stereoselective cobalt-catalyzed hydrovinylative cyclization of 1,6-enynes with chalcones to obtain functionalized pyrrolidines has been developed. The products were furnished in good yields with up to 93% ee. A plausible mechanism through which the transformation was initiated by cyclization of 1,6-enynes is proposed.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Multidisciplinary
Eduardo Garcia-Padilla, Imma Escofet, Feliu Maseras, Antonio M. Echavarren
Summary: Through computational analysis, we have identified the dominant structures of the intermediates of gold(I)-catalyzed cyclizations of 1,5-enynes and 1,5-allenenes, including gold(I) cyclopropylcarbenes, endocyclic vinylgold complexes and previously unreported non-classical carbocationic minima. Cyclopropylcarbene structures are consistently favored as the most stable intermediates for all studied substitution patterns.
Article
Chemistry, Organic
Zhantao Yang, Zhiqiang Yu, Yulin He, Wei Feng, Yinchao Zhang, Junjie Wang, Xiangtao Kong, Chun-Hua Yang
Summary: A Rh-catalyzed regioselective, stereoselective carbocyclization/borylation reaction of acrylate-containing 1,6-enynes was developed, enabling the synthesis of versatile and densely functionalized pyrrolidine compounds. The reaction allows for the formation of pyrrolidines with either (Z) or uncommon (E) geometry at the double bond, depending on the substituent on the alkyne, with sterically hindered and conjugative aryl groups favoring the latter configuration. The reaction also leads to the formation of a tetrasubstituted vinyl boronate, containing an all-carbon quaternary stereocenter.
Article
Chemistry, Organic
Ran Ding, Ya-Li Liu, Hui Hao, Chuan-Yi Chen, Lei Liu, Nian-Shou Chen, Yu Guo, Pei-Long Wang
Summary: A copper(I)-catalyzed sulfonylation-cyclization method has been developed for the transformation of 1,5-dienes with sulfonyl chlorides. The reaction exhibits a wide substrate scope and excellent regioselectivity, resulting in the formation of derivatized 1,5-dihydro-2H-pyrrol-2-one scaffold in one pot.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Organic
Feilong Sun, Chengxi Yang, Jie Ni, Gui-Juan Cheng, Xianjie Fang
Summary: A regiodivergent nickel-catalyzed hydrocyanation of 1-aryl-4-silyl-1,3-diynes is reported, where appropriate ligands result in high yields and regioselectivities of two different enynyl nitriles. DFT calculations show that different ligands lead to diverse alkyne insertion modes, impacting the regioselectivity. The synthetic value of cyano-containing 1,3-enynes is demonstrated through downstream transformations.
Article
Chemistry, Organic
Aureilien Dupeux, Emilie Gentilini, Veironique Michelet
Summary: Gold-catalyzed Prins-type cyclizations are a fascinating approach for synthesizing complex molecules with excellent stereochemistry. Researchers have developed a new and efficient system for this reaction, achieving yields up to 89% in 13 examples. They also reported the first enantioselective version of a gold-catalyzed Prins-type cyclization using a chiral TADDOL-based Au(I) phosphonite complex, yielding highly enantiomerically enriched products (>99% ee) after crystallization.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Applied
Romain Melot, Sandra Olivero, Veronique Michelet
Summary: A synthetic route for alkynylated saturated N-heterocycles was developed via a sequential combination of Shono oxidation and gold(I)-catalyzed alkynylation reaction. The electrochemical Shono oxidation enabled efficient access to various N,O-acetals through direct C-H bond functionalization of cyclic amines. The gold-catalyzed process allowed the introduction of aryl acetylene partners with different electron properties. Promising initial results on asymmetric version were obtained.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Organic
Jingwen Zeng, Wei Fang, Bijin Lin, Gen-Qiang Chen, Xumu Zhang
Summary: In this Letter, a highly enantioselective rhodium(I)-catalyzed Alder-ene-type cycloisomerization of 1,7-enynes is disclosed, offering an efficient method for the synthesis of a wide range of fused six-membered cyclic compounds. Furthermore, a high turnover frequency experiment and deuterium-labeling experiment were performed to give insight into this transformation.
Article
Chemistry, Organic
Jhen-Kuei Yu, Constantin Czekelius
Summary: An efficient protocol for the synthesis of 3-ethynyl-2-aryl-bicyclo[3.1.0]hexenes through gold-catalyzed enyne cyclization was established. Depending on the substitution pattern, unusual cationic rearrangements of the corresponding gold carbene were revealed, leading to the formation of cyclohexadienes or 5,9-methanobenzo[8]annulene derivatives, respectively.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Review
Chemistry, Applied
Wen-Ting Wei, Qiang Li, Ming-Zhong Zhang, Wei-Min He
Summary: N-radicals have been relatively unexplored compared to carbon-centered radicals, but recent advancements in radical chemistry have led to the development of various production methods for N-radicals. These N-radicals play crucial roles in the cyclization of 1,n-enynes, providing a new synthetic pathway for the preparation of complex cyclic systems and natural products containing elaborate ring frameworks.
CHINESE JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Organic
Wen-Bo Shen, Ting-Ting Zhang, Meng Zhang, Jing-Jing Wu, Xiao-Lei Jiang, Guang-Xin Ru, Guang-Qin Gao, Xiu-Hong Zhu
Summary: The oxidative cyclization of diynes with pyridine N-oxides using an amide directing group is achieved with the help of catalysts such as copper and gold. Selective activation of non-polarized and aminated alkynes by these metals leads to the synthesis of a variety of pyrroles and dihydroindeno[1,2-c]pyrrol-3(2H)-ones. The difference in reactivity is suggested to be due to the multicoordinated Cu center and the linearly aligned dicoordinated Au center.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Review
Chemistry, Organic
Zhenzhi Cai, Sven Trienes, Kairui Liu, Lutz Ackermann, Yan Zhang
Summary: During the past decade, photo- and electrochemical reactions via single-electron-transfer (SET) triggered radical pathways have been widely used to efficiently form chemical bonds. In particular, radical cyclization reactions of 1,n-enynes have been explored for the synthesis of bioactive compounds. This minireview summarizes recent progress in radical cascade cyclizations of 1,n-enynes (n = 5, 6, and 7) under photo/electrochemical conditions until September 2023, providing a categorized overview and understanding for readers.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Ariel L. Burgio, Nicklas W. Buchbinder, Webster L. Santos
Summary: A facile method for the synthesis of (Z)-1,3-enynes is achieved through sequential copper-catalyzed regio- and stereoselective borylation-protodeboronation of 1,3-diynes. Pinacolborane, copper(II) acetate, and Xantphos are utilized as the ligand to efficiently introduce hydrogen and Bpin in a cis fashion, followed by rapid hydrolysis with water. The reaction exhibits wide substrate scope and proceeds in a chemoselective manner.
Article
Chemistry, Multidisciplinary
Chenxiao Qi, Guillaume Force, Vincent Gandon, David Leboeuf
Summary: A novel method for haloamidation is introduced in this paper, providing new building blocks for drug discovery. This method overcomes some limitations of traditional reactions and the reaction mechanism is deeply studied, which is expected to promote the development of more complex transformations in this field.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Shengdong Wang, Guillaume Force, Jean-Francois Carpentier, Yann Sarazin, Christophe Bour, Vincent Gandon, David Leboeuf
Summary: A modular one-pot synthesis of 9,10-dihydroacridine frameworks was achieved through a reaction sequence involving selective ortho-C alkenylation of diarylamines with aryl alkynes followed by intramolecular hydroarylation. The combination of hexafluoroisopropanol and triflimide as catalysts played a crucial role in triggering the whole process.
Article
Chemistry, Applied
Lucile Marin, Soufyan Jerhaoui, Emilie Kolodziej, Regis Guillot, Vincent Gandon, Francoise Colobert, Emmanuelle Schulz, Joanna Wencel-Delord, David Leboeuf
Summary: A stereoselective aza-Piancatelli reaction has been developed for the synthesis of 4-aminocyclopentenones, using chiral o-sulfinyl anilines as chiral inductors. The targeted products can be obtained in good to excellent yields, with high drs up to >95:5 depending on the furan substitution pattern.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Guillaume Force, Anna Perfetto, Robert J. Mayer, Ilaria Ciofini, David Leboeuf
Summary: A new strategy employing a mixed anhydride with a pentafluorophenyl group is described for the convenient synthesis of macrolactones and other products. Kinetic studies and DFT computations were used to rationalize the reactivity of the pentafluorophenyl group in the reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Allegra Franchino, Alex Marti, Antonio M. Echavarren
Summary: A new strategy for enantioselective transition-metal catalysis is presented, where precise positioning of chiral counteranions responsible for asymmetric induction is achieved by placing a H-bond donor on the ligand of a cationic complex. This paradigm was successfully implemented in 5-exo-dig and 6-endo-dig cyclizations of 1,6-enynes, allowing the use of chiral anions in Au(I)-catalyzed reactions of challenging alkyne substrates. Experimental evidence confirmed the crucial H-bonding interaction at the heart of the catalytic system.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Ulysse Caniparoli, Imma Escofet, Antonio M. Echavarren
Summary: Planar chiral monodentate 1,3-disubstituted ferrocene phosphines inspired by JohnPhos-type ligands have been synthesized and applied for the enantioselective gold(I) catalyzed [4 + 2] cycloaddition of 1,6-arylenynes. Computational studies elucidated the working mode of the catalyst, involving attractive noncovalent interactions that induce the folding of the substrate in the chiral environment of the ligand.
Article
Chemistry, Physical
Marie Vayer, Shaofei Zhang, Joseph Moran, David Lebaeuf
Summary: This article describes a general method for the reduction of styrene oxides, which is both linear-selective and compatible with strongly electronically deactivated substrates. The reaction is user-friendly and does not require special reagents or atmosphere conditions.
Article
Chemistry, Physical
Marie Vayer, Robert J. Mayer, Joseph Moran, David Leboeuf
Summary: We demonstrate a promoter system featuring triflic acid and hexafluoroisopropanol that enables the direct construction of trifluoromethylated all-carbon quaternary centers, significantly expanding the scope of hydroarylation of unactivated styrenes and providing a straightforward approach to trifluoromethylated diarylalkanes of interest.
Article
Chemistry, Multidisciplinary
Valentyn Pozhydaiev, Marie Vayer, Claire Fave, Joseph Moran, David Leboeuf
Summary: We report a new one-pot protocol for the synthesis of beta-arylethylamines, which allows the direct entry to unprotected compounds with remarkable functional group tolerance. This method involves the 1,2-aminoarylation of alkenes using hydroxylammonium triflate salts and (hetero)arenes. The combination of hexafluoroisopropanol as a solvent and an iron(II) catalyst is crucial for the synthesis of nitrogen-containing molecules.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Tommaso Bortolato, Gianluca Simionato, Marie Vayer, Cristian Rosso, Lorenzo Paoloni, Edmondo M. Benetti, Andrea Sartorel, David Leboeuf, Luca Dell'Amico
Summary: This study reports the design and characterization of 9-aryl dihydroacridines (9ADA) and 12-aryl dihydrobenzoacridines (12ADBA) as strong reducing organic photocatalysts. These photocatalysts exhibit locally excited or charge-transfer excited states, and can perform photoredox defunctionalization processes and atom transfer radical polymerization under visible light. They also feature a catalytic multisite proton-coupled electron transfer (MS-PCET) mechanism, enabling the reduction of redox-inert substrates under single-photon excitation. These new photocatalysts are expected to open new mechanistic pathways in the field of photocatalysis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Andrea Cataffo, Miguel Pena-Lopez, Riccardo Pedrazzani, Antonio M. Echavarren
Summary: This study presents two classes of stereoselective cyclizations using a chiral auxiliary approach. The first class involves the stereoselective cascade cyclization of 1,5-enynes using Oppolzer camphorsultam as chiral auxiliary, leading to the synthesis of enantioenriched spirocyclic ketones. The second class focuses on the stereoselective alkoxycyclization of 1,6-enynes mediated by Evans-type oxazolidinone, resulting in the formation of enantioenriched beta-tetralones after removal of the auxiliary.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Alex Marti, Gala Ogalla, Antonio M. Echavarren
Summary: The enantioselective reaction of 1,6-enynes with O-, N-, and C-nucleophiles has been achieved through matched ion pair gold(I) catalysis. The chiral gold(I) cation and anion are H-bonded through a urea group, leading to very high levels of enantiocontrol (>99:1 er) for a wide range of substrates. DFT studies highlight the importance of the H-bond donor group in anchoring the matched chiral cation- and anion-favoring additional noncovalent interactions.
Article
Chemistry, Multidisciplinary
Cyprien Muller, Filip Horky, Marie Vayer, Andrei Golushko, David Leboeuf, Joseph Moran
Summary: This paper describes a new variant of the oxa-Pictet-Spengler reaction using epoxide as a starting material, which greatly expands the scope and rate of the reaction. By using hexafluoroisopropanol as a solvent, the electrophile scope of the reaction includes ketone analogues, aliphatic aldehydes, and phenylacetyl aldehydes, and the nucleophile scope includes moderately electronically deactivated and highly substituted beta-phenylethanols. In addition, the products can be further modified in the same system by subsequent ring-opening, reductions, and intra- and intermolecular Friedel-Crafts reactions. Finally, the synthesis of drug analogues demonstrates the pharmacological relevance of the isochroman motif.
Article
Chemistry, Multidisciplinary
Eduardo Garcia-Padilla, Imma Escofet, Feliu Maseras, Antonio M. Echavarren
Summary: Through computational analysis, we have identified the dominant structures of the intermediates of gold(I)-catalyzed cyclizations of 1,5-enynes and 1,5-allenenes, including gold(I) cyclopropylcarbenes, endocyclic vinylgold complexes and previously unreported non-classical carbocationic minima. Cyclopropylcarbene structures are consistently favored as the most stable intermediates for all studied substitution patterns.
Article
Chemistry, Multidisciplinary
Nicolas Zeidan, Sergiu Bicic, Robert J. Mayer, David Leboeuf, Joseph Moran
Summary: This study demonstrates that HFIP greatly expands the scope of the Bronsted acid-catalyzed hydroarylation of enamides, and acts as a slow-release reservoir for the key cationic intermediate. The reaction is fast and practical, and can prevent the oligomerization of the substrate.