Article
Chemistry, Organic
Lukas Hoff, Simon D. Schnell, Andrea Tomio, Anthony Linden, Karl Gademann
Summary: A silver-mediated Pd-catalyzed cross-coupling method for 3-bromo-1,2,4,5-tetrazine with boronic acids was presented in this study. It was found that electronic modification of the dppf ligand played a crucial role in achieving good turnover. Using this fast method, a variety of alkyl-, heteroatom-, and halide-substituted aryl- and heteroaryl-tetrazines were successfully prepared, with yields up to 87%.
Review
Biochemistry & Molecular Biology
Ignacio E. Tobal, Rocio Bautista, David Diez, Narciso M. Garrido, Pilar Garcia-Garcia
Summary: Building blocks play a crucial role in synthetic organic chemistry, with the Diels-Alder cycloaddition reaction being a common application. Cyclic dienes are important for facilitating this reaction. By utilizing cyclic dienes with unique characteristics, biologically active compounds with interesting properties can be synthesized.
Article
Chemistry, Organic
Casper Larsen Barlose, Jonas Faghtmann, Rene Slot Bitsch, Joseph Daniel Gbubele, Karl Anker Jorgensen
Summary: The combination of asymmetric organocatalysis with the (pseudo)-halogen effect allows for the efficient formation of chiral norcarane scaffolds. These scaffolds can easily undergo rearrangements or lactonization to form intricate chiral ring structures.
Article
Chemistry, Multidisciplinary
Qiuyu He, Lirong Cao, Yiran Wei, Gregory R. Dake
Summary: The utility of 2-diphenylphosphoryloxy-1,3-dienes for constructing substituted nitrogen heterocycles is demonstrated. These dienes undergo boron trifluoride-promoted aza-Diels-Alder reactions with imines or related species formed in situ using aldehydes and amine derivatives. The stability of the dienes allows for a three-component reaction without the need for special precautions. The enol phosphate functional group is highlighted for further reactions, generating functionalized piperidenes or pyridines.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Xin-Qi Zhu, Qian Wang, Jieping Zhu
Summary: This study reports chiral phosphoric acid-catalyzed enantioselective Diels-Alder reactions and three-component reactions, which can efficiently synthesize compounds with multiple functional groups in high yields and stereoselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Carmen Najera, Jose M. Sansano, Miguel Yus
Summary: This paper explores the Diels-Alder reactions of various 1-amino-1,3-dienes with dienophiles, focusing on the synthesis of polycyclic nitrogen-containing heterocycles, particularly alkaloids. The methodology presented here offers a simple and selective approach to obtaining N-containing heterocyclic compounds in a single step, creating multiple carbon-carbon bonds in a regio-, diastereo-, and enantioselective manner.
Article
Chemistry, Organic
Yusuke Tomita, Naoto Haraguchi, Sayori Kiyota, Nobuyuki Komine, Masafumi Hirano
Summary: A traditional cobalt catalyst system has been found to exhibit previously undiscovered reactivity. Depending on the choice of tertiary phosphines and substrates, this catalytic system can catalyze diverse cycloadditions, yielding various cyclic compounds. The bite angles of the ligands used significantly contribute to the catalytic diversity.
Article
Chemistry, Organic
Elisa Brambilla, Sara Leoni, Giorgio Abbiati, Valentina Pirovano, Elisabetta Rossi
Summary: Spiroindolenines were used as cyclic imine substrates in formal aza-Diels-Alder reactions with Danishefsky's diene or silyloxy-substituted electron-rich dienes, leading to the synthesis of tetrahydropyrido[1,2-a]spiroindolinones under mild conditions in the presence of ytterbium triflate as a Lewis acidic catalyst, with good yields. The reaction results in the preparation of a small library of a new class of conformational constrained heterocyclic derivatives that easily undergo selective and efficient manipulations.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Hilal Ahmad Khan, Vikiho Wotsa, J. Lavanya, Chinnapan Sivasankar
Summary: In this study, a straightforward method for the direct synthesis of 1,1,3,4-tetrasubstituted conjugated dienes was reported. The reaction, which utilizes allyl bromides and alpha-diazoesters as substrates, can be carried out at room temperature and is compatible with various electron donating and electron withdrawing groups. The reaction also tolerates various bromide substituted reactants.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Organic
Shuheng Xu, Linwei Zeng, Sunliang Cui
Summary: The Diels-Alder (DA) reaction and hetero-Diels-Alder (HDA) reaction are powerful methods for constructing carbocycles and heterocycles. This study presents an integrated building block that combines both DA and HDA reactions, utilizing triazenyl dienes to undergo the DA reaction and the newly released alkene moiety and triazene to engage in the HDA reaction.
Article
Chemistry, Organic
Yuvraj Garg, James Osborne, Serhii Vasylevskyi, Nivedha Velmurugan, Fujie Tanaka
Summary: 1,3-Diamine-derived catalysts were synthesized and utilized in asymmetric Mannich reactions of ketones. The Mannich products with high enantioselectivities were obtained under mild conditions through catalysis by one of the 1,3-diamine derivatives in the presence of acids. Bond formation primarily occurred at the less-substituted α-position of the ketone carbonyl group. The primary and tertiary amines of the 1,3-diamine derivative cooperatively acted for the catalysis.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Dengfu Lu, Lei Chen, Avishek Roy, Zhendong Jin
Summary: 1,3-Dienes derived from (R)-4-t-butyldimethylsilyloxy-2-cyclohexen-1-one react with acyl nitroso dienophiles to form exclusively anti [4 + 2] cycloaddition products. These regio and diastereoselective reactions increase the asymmetric complexity from one chiral center in the starting material to three chiral centers in the products in a single step, providing a powerful approach for the asymmetric synthesis of compounds containing 3,6-dihydro-1,2-oxazine structural feature.
TETRAHEDRON LETTERS
(2023)
Article
Chemistry, Organic
Xiaoxiao Chen, Guoxiang Zhang, Rong Zeng
Summary: The synergistic utilization of copper catalysis and proton-transfer catalysis allows for an atom- and step-economic aza-[4 + 2] cycloaddition reaction between N-arylamino carbonyl compounds and simple 1,3-dienes. This operationally simple protocol provides a green, rapid, and efficient access to 1,2,3,6-tetrahydropyridines with a broad scope.
Article
Chemistry, Organic
Kristina C. Probasco, Michael P. Jennings
Summary: The NXS-mediated halogenation reaction of (E)-alpha-trimethylsilyl-beta-alkyl(aryl)-alpha,beta-unsaturated esters in DMF resulted in the formation of (Z)-beta-substituted-alpha-halogenated-alpha,beta-unsaturated ester products with moderate to high yields. The reaction mechanism involves an initial halonium cation intermediate and regioselective ring opening with DMF, leading to the stereoselective formation of vinylic bromo- and chloroesters.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Khaled Youssef, Magali Allain, Thomas Cauchy, Frederic Gohier
Summary: 2-Bromo, 3-bromothiophene, 2,5-dibromothiophene, 3,4-dibromothiophene, and perbrominated thiophene were oxidized under different conditions to form thiophene S,S-dioxide. Depending on the substitution, sulfone was obtained when the hindered thiophene was used. However, monosubstituted thiophenes could not be transformed into sulfone due to the reactivity of the sulfoxide intermediate, which led to dimerization. The structures were confirmed through the obtaining of crystals. The oxidation of 3,4-dibromothiophene could either result in the formation of cycloadduct or the isolation of sulfone, which could further evolve into benzothiophene sulfone.
NEW JOURNAL OF CHEMISTRY
(2023)
