Article
Chemistry, Physical
Raju S. Thombal, Peter Yuosef M. Rubio, Daesung Lee, Debabrata Maiti, Yong Rok Lee
Summary: Metal catalyzed cascade C-H activation/annulation is a highly promising approach for the construction of aromatic and heteroaromatic compounds. Pd-complexes play a crucial role in this method, enabling high catalytic efficiency through the activation of molecules bearing a directing group.
Article
Chemistry, Applied
Kenji Matsumoto, Rina Nakano, Ken-ichi Yamada, Tsukasa Hirokane, Masahiro Yoshida
Summary: This study reports an efficient platform for the one-step construction of nitrogen-containing polycyclic frameworks using a heterogeneous platinum-catalyzed oxidative alpha,beta-C(sp(3))-H dual functionalization of saturated cyclic amines. By conducting a tandem oxidative dehydrogenation/hetero Diels-Alder reaction under mild aerobic conditions, tetracyclic octahydro-dipyrroloquinoline frameworks were synthesized in good yields. The reaction was successfully applied to the one-step synthesis of natural products incargranine B aglycone and seneciobipyrrolidine. This study provides an efficient and rapid approach to nitrogen-containing fused tetracyclic compounds in a highly atom-economical manner.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Review
Chemistry, Applied
Ahmad Saifuddin Mohamad Arshad, Mohd Nizam Mordi
Summary: Carbolines are a prominent class of tricyclic alkaloids found in natural products, and there are four different regioisomers known. Synthetic methods have been established for the construction of carboline frameworks, both requiring customized approaches for each regioisomer and unified approaches capable of generating multiple regioisomers. This review summarizes the construction of isomeric carbolines based on unified synthetic approaches.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Review
Chemistry, Multidisciplinary
Sandeep Kumar, Akshay Kumar, Dharminder Sharma, Pralay Das
Summary: Directing groups are widely used for transition metal-catalyzed direct C-H bond functionalization, with recent advancements in utilizing free amine, hydroxyl and sulfhydryl as directing groups for the synthesis of heterocycles.
Article
Chemistry, Organic
Qinghe Gao, Zhenhua Sun, Qinfei Xia, Ruonan Li, Wenlong Wang, Siwei Ma, Yixin Chai, Manman Wu, Wei Hu, Peter Abranyi-Balogh, Gyorgy M. Keseru, Xinya Han
Summary: A new general synthesis method has been developed to prepare pharmaceutically important azolo[1,5-a]pyrimidines starting from commonly available 3(5)-aminoazoles, aldehydes, and triethylamine. This direct and practical strategy allows the construction of a variety of compounds, including pyrazolo[1,5-a]pyrimidines and [1,2,4]triazolo[1,5-a]pyrimidines, with the capability to synthesize zaleplon, a clinically used drug.
Article
Chemistry, Multidisciplinary
Johannes Grosskopf, Alexandra A. Heidecker, Thorsten Bach
Summary: Racemic 3-substituted oxindoles can be converted into enantiomerically pure or enriched material through photochemical deracemization process. Light energy compensates for the loss of entropy and enables predictable editing of the stereogenic center. The obtained oxindoles are valuable intermediates for further transformations with complete retention at the stereogenic center.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Tao Liu, Lingli Han, Jing Zhang, Gang Lu
Summary: Density functional theory calculations were used to investigate the competing pathways of rhodacycle intermediates in Rh(III)-catalyzed annulations of 2-alkenyl phenols and 2-alkenyl anilides with alkynes. The results reveal that the multiple pathways of eight-membered rhodacycles can be subtly tuned to give specific cyclic products. The formation of different cyclic products from 2-alkenyl phenols and 2-alkenyl anilides is governed by different pathways involving the dissociation of Rh-O bond and intramolecular olefin migratory insertion, respectively.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Tomas J. Saiegh, Christophe Meyer, Janine Cossy
Summary: Hydroxamates derived from 3-sulfolene-3-carboxylic acid can undergo intra- and intermolecular rhodium(III)-catalyzed heteroannulations, involving C(sp(2))-H bond activation. These reactions provide a direct route to diversely substituted pyridones and pyridines fused to a sulfolene ring. The subsequent cheletropic elimination under microwave irradiation leads to the generation of pyridine ortho-quinodimethanes.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Review
Chemistry, Multidisciplinary
Marc Font, Moises Gulias, Jose Luis Mascarenas
Summary: The selective functionalization of C(sp(3))-H bonds using transition-metal catalysis is an important transformation in modern synthetic chemistry, although it poses significant challenges. There has been notable progress in recent years, particularly in the development of new intermolecular reactions. Conversely, the research on assembling cyclic products from simple acyclic precursors using metal-catalyzed C(sp(3))-H bond activations has been relatively limited.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Jakub Brzeskiewicz, Rafal Loska
Summary: The palladium-catalyzed C(sp2)-H functionalization of bromoaryl aldonitrones leading to benzocyclobutenone-derived ketonitrones is described, allowing for the preparation of a wide range of strained, four-membered ketonitrones with broad functional group tolerance. Downstream transformations of the formed products were demonstrated, illustrating the synthetic utility of the obtained benzocyclobutenone-derived nitrones for the construction of polycyclic nitrogen-containing scaffolds.
Article
Chemistry, Multidisciplinary
Johannes Grosskopf, Manuel Plaza, Roger Jan Kutta, Patrick Nuernberger, Thorsten Bach
Summary: 2,5-Diketopiperazines are cyclic dipeptides with a wide range of applications, and their enantioselective preparation can be achieved through photochemical deracemization, allowing for stereochemical editing at a single position while maintaining other stereogenic centers unaffected. The chiral benzophenone catalyst in combination with irradiation at lambda=366 nm enables the establishment of configuration at the stereogenic carbon atom C6 at will.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Tuanli Yao, Jiazhe Hui, Tao Liu, Tao Li
Summary: A palladium-catalyzed multicomponent reaction has been developed for the synthesis of o-alkylated arylacrylates and stilbenes through tandem intramolecular Heck cyclization/aryne dicarbofunctionalization, providing a straightforward method for accessing these compounds.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Balu Ramesh, Masilamani Jeganmohan
Summary: This paper describes a Co(III)-catalyzed regio- and chemoselective redox-neutral C-H annulation of arylamides/acrylamides with 1,3-dienes. The reaction is well-suited for less-reactive 1,3-butadiene and enables the synthesis of pharmaceutically important 3,4-dihydroisoquinolinones in good yields. The prepared 3,4-dihydroisoquinolinones can then be converted into highly important oxirane derivatives in good yields. A plausible mechanistic cycle is proposed and supported by a competition experiment and kinetic isotopic effect (KIE) studies.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Review
Chemistry, Multidisciplinary
Takashi Koike, Munetaka Akita
Summary: The electron is unique and has the ability to participate in various systems, with novel electron injection methods revolutionizing chemical bond formation techniques in organic synthesis. In particular, visible-light organic photoredox catalysis has rapidly spread among synthetic chemists due to its sustainability and versatility.
TRENDS IN CHEMISTRY
(2021)
Article
Chemistry, Organic
Ayumi Inami, Yuji Nishii, Koji Hirano, Masahiro Miura
Summary: In this study, a new synthetic method was developed using vinyl selenone as a surrogate for phenylacetylene in the Rh-catalyzed annulative coupling reaction. This method successfully produced 3,4-nonsubstituted isoquinoline compounds. The reaction conditions were mild and the vinyl selenone could be recovered and recycled.
