Article
Chemistry, Organic
Dianpeng Chen, Jianming Li, Xiuhua Zhang, Gongle Liu, Xin Wang, Yongwei Liu, Xuan Liu, Yingying Shan
Summary: A novel method for the synthesis of fused tetracyclic N-heterocycles is described using palladium-catalyzed cyclization of isocyanides with alkyne-tethered aryl iodides. The reaction involves a unique amino-to-alkyl 1,5-palladium migration/intramolecular C(sp(3))-C(sp(2)) coupling sequence. Isocyanide plays multiple roles in this transformation, serving as a C1 synthon, a C1N1 synthon, and the donor of C(sp(3)) for C(sp(3))-C(sp(2)) coupling, and it represents the only successful example of C(sp(3))-H activation of isocyanide.
Article
Chemistry, Organic
Y. Bharath Chaithanya Kumar, Polasani Samatha, Prathama S. Mainkar, Raju Adepu
Summary: Rhodium catalyzed alkyne-tethered intramolecular annulation has been successfully demonstrated for the synthesis of tetracyclic carbazole skeletons, resulting in a series of five to eight-membered pyrido[3,2,1-jk]carbazoles. This atom economical annulation proceeds under mild reaction conditions and offers a broad substrate scope.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Organic
Jian Xiao, Ya-Wen Wang, Zhong-Ping Qiu, Yu Peng
Summary: The facile access to the tetracyclic skeleton of podophyllotoxin, a medicinally important lignan natural product, was efficiently achieved via a unique intramolecular alkylarylation of the tethered alkene in a dihalide under mild conditions using reductive nickel catalysis.
Article
Chemistry, Organic
Kirsten A. Hewitt, Claire A. Herbert, Elizabeth R. Jarvo
Summary: A nickel-catalyzed intramolecular conjunctive cross-electrophile coupling reaction has been developed for the synthesis of 3,5-vicinal carbocyclic rings found in various biologically active compounds and natural products. Mechanistic experiments suggest that the reaction proceeds through alkyl iodides formed in situ, initiates at the secondary electrophilic center, and proceeds via radical intermediates.
Article
Chemistry, Applied
Kang Wu, Tian-Zhang Wang, Yu-Feng Liang
Summary: This nickel-catalyzed reductive cross coupling reaction allows for the efficient generation of structurally diverse thioesters by activating carboxylic acids with disulfides. The reaction demonstrates broad substrate scope and wide functional group tolerance, making it a convenient and practical tactic for constructing carbon-sulfur bonds.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Organic
Qian Tu, Zheyuan Wang, Zhongchao Zhang, Jun Huang, Zhen Yang
Summary: The structurally intriguing tetracyclic core of complex harziane diterpenoid was successfully constructed in 14 steps from commercially available compound. Key methods used include Mn/Cu-mediated oxidative 1,3-dicarbonyl radical cascade cyclization reaction and Au-catalyzed diastereoselective formal [2 + 2] cycloaddition.
Article
Chemistry, Multidisciplinary
Takeshi Yamada, Sentaro Okamoto
Summary: The interrupted Passerini reaction of 3-(2-isocyanoethyl)-indole catalysed by 3,5,6-trifluoro-2-pyridone was studied. The reaction afforded a diastereoselective tetracyclic furolindoline, which showed good reactivity in the Joullie-Ugi reaction. Therefore, one-pot sequential Passerini/Joullie-Ugi reactions were performed to rapidly obtain versatile and highly functionalised furoindolines from 3-(2-isocyanoethyl)-indole.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Hu Jingping, Chen Wenqing, Jiang Yuyang, Xu Jing
Summary: Among the small subfamily of Daphniphyllum alkaloids, the daphnezomine A-type alkaloids have only three known members, namely daphnezomine A, daphnezomine B, and dapholdhamine B. These alkaloids possess a unique aza-adamantane core and nine contiguous stereogenic centers, which present significant synthetic challenges. The synthesis of the tetracyclic core structure of compounds 1 and 2 has been reported, with key steps including a Huang's amide-activation-annulation and a Hutchins-Kabalka reductive rearrangement.
CHINESE JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Subrata Sahoo, Shantanu Pal
Summary: An efficient and atom-economical palladium-catalyzed intramolecular cross dehydrogenative coupling (CDC) reaction has been developed for constructing highly pi-conjugated compounds using molecular oxygen as sole oxidant. The method has wide substrate scope, good functional group tolerance, and can generate fluorescence active compounds with high quantum yield. Additionally, the synthetic versatility of the method is showcased through Fe-catalyzed reductive isoxazole ring cleavage towards heteropolycyclic compounds.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Jeff K. Kerkovius, Alice R. Wong, Victor W. Mak, Sarah E. Reisman
Summary: The formation of quaternary stereogenic centers in polycyclic systems is achieved via a strategy based on the semi-pinacol reaction. Two fragments of similar size and complexity are joined by alkenyl lithium addition to an epoxy ketone, followed by a semi-pinacol rearrangement. Polycyclic scaffolds with quaternary stereogenic centers are generated in high yields, tolerating various functional groups. This method provides a useful strategy for the synthesis of complex polycyclic natural product-like scaffolds.
Article
Chemistry, Organic
H. Surya Prakash Rao, J. Prabhakaran
Summary: The methodology involves a palladium-(II) catalyzed intramolecular Buchwald-Hartwig C-N coupling to access tetracyclic heterocyclic compounds. It is versatile, highly efficient, and has a wide scope for the synthesis of medicinally important tetracyclic C(3)-aminoisoindolinones.
SYNTHETIC COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Saiprasad Nunewar, Sanjeev Kumar, Harishchandra Pandhare, Srinivas Nanduri, Vinaykumar Kanchupalli
Summary: The study reports the highly tunable selectivity of Rh(III)-catalyzed annulations of N-carboxamide indoles with iodonium ylides, leading to the formation of synthetically important N-heterocycles. The protocol is operationally simple, provides novel scaffolds, and can be easily scaled up.
Article
Chemistry, Organic
Jiwei Wang, Gendi Wang, Xiang Cheng, Ye Liu, Jun Zhang
Summary: A practical and efficient one-pot protocol for the synthesis of 2,3-diarylindoles via Pd-catalyzed bis-arylative cyclization has been developed. Mechanism studies revealed a Sonogashira reaction followed by intramolecular aminopalladation/cross-coupling to access the desired products. The methodology shows a broad substrate scope and can produce various 2,3-diarylindoles with two different aryl groups.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Physical
Xi Zhang, Juan Wang, Shang-Dong Yang
Summary: This study presents a general process for the enantioselective Co-catalyzed reductive cross-coupling reaction, successfully constructing C(sp(2))-C(sp(2)) bonds and obtaining axially chiral phosphine oxide compounds with good enantioselectivity. The catalyst system shows practical potential in forming axially chiral ligands and other functional atropisomers.
Article
Chemistry, Organic
Fu-Yu Li, Bei Wang, Hong Xu, Yao Xiao, Dong-Wei Huang, Ji-Yu Wang
Summary: The convenient synthesis of diverse and complex poly-substituted beta-alkenyl valerolactones is achieved through Fe(iii)-catalyzed reduction radical tandem strategy of 2,3-dienoates and allyl alcohols. The allyl alcohols can undergo simultaneous transformations into alkyl radicals and allyl ester intermediates under Fe(iii) catalysis, which then react via Michael addition to form the desired products. Notably, this method also enables the preparation of spiro-valerolactones and cyclo-valerolactones, as well as the transformation of beta-alkenyl valerolactones into previously unreported pyrazole lactone compounds.
ORGANIC CHEMISTRY FRONTIERS
(2023)
