Article
Chemistry, Multidisciplinary
Heng-Zhi Tian, Qing-Gang Tang, Guo-Qiang Lin, Xing-Wen Sun
Summary: A novel approach to synthesize chiral 1,2-oxazinane spirocyclic scaffolds by organocatalytic [4 + 2] cycloaddition reaction has been developed. In addition, a hydrazide 1,4-synthon is synthesized to construct chiral hexahydropyridazin spirocyclic scaffolds. Both reactions exhibit good to excellent yield, diastereoselectivity, and enantioselectivity.
Article
Chemistry, Organic
Tania I. I. Ramirez-Candelero, Carlos A. A. Gonzalez-Gonzalez, Aydee Fuentes-Benites, Eduardo Diaz-Torres, Joaquin Tamariz, Ruben A. Toscano, Salvador Mastachi-Loza
Summary: Spirocyclic compounds have attracted extensive research interest in recent years due to their diverse properties and wide range of industrial and pharmacological applications. This study aimed to synthesize new multifunctional spirocyclic compounds from tetrahydrobenzoxazolones, which served as versatile starting materials for the elaboration of more complex molecules. The resulting spirocyclic compounds were then functionalized in various ways.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Biao Wang, Xiao Yan, Han Zhong, Ouyang Qin, Xu Tian
Summary: This study reports the regiodivergent [2 + 2] cycloaddition and ene reactions of 1,2-dihydroquinolines with 3-olefinic oxindoles. The reactions yield products with different yields and stereoselectivities depending on the catalyst used.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Applied
Sloan Ayers, Gregory L. Beutner, Wei Ding, Carolyn Higman, Charles Pathirana, Robert Wethman
Summary: Having reliable methods to monitor catalyst activation processes is crucial for ensuring the reproducibility of catalytic reactions. For asymmetric Diels-Alder reactions, chiral oxazaborolidine or oxazaborolidinium catalysts are powerful reagents that promote these reactions with high yield and selectivity. By investigating the mechanism, several modern analytical methods are compared to quantitate the formation of oxazaborolidine catalyst from amino alcohol and boroxine, leading to useful monitoring methods for this important transformation.
ORGANIC PROCESS RESEARCH & DEVELOPMENT
(2022)
Article
Chemistry, Multidisciplinary
Rupkumar Khuntia, Sanat Kumar Mahapatra, Lisa Roy, Subhas Chandra Pan
Summary: In this study, a new method has been developed to rapidly synthesize structurally diverse and complex molecules from easily available starting materials through catalytic reactions. Through the analysis of the mechanistic intricacies, the roles of chiral and Lewis base catalysts in the reaction have been investigated.
Article
Chemistry, Multidisciplinary
Rupkumar Khuntia, Sanat Kumar Mahapatra, Lisa Roy, Subhas Chandra Pan
Summary: An important goal in organic synthesis and medicinal chemistry is to efficiently and affordably synthesize structurally diverse and complex molecules from readily available starting materials. In this study, a protocol for the synthesis of benzofuran fused azocine derivatives and spiro-cyclopentanone benzofurans has been developed. The method involves sequential catalysis with chiral H-bonding catalyst and Lewis base catalyst. The products exhibit high yields and high stereo- and enantioselectivities.
Article
Chemistry, Organic
Yong-Chao Ming, Xue-Jiao Lv, Ming Liu, Yan-Kai Liu
Summary: An efficient aminocatalytic enantioselective double-activation strategy has been developed to synthesize chiral polycyclic tetrahydrocarbazole and chromane derivatives with excellent diastereo- and enantioselectivities.
Article
Chemistry, Organic
Yuhang Xue, Jianbo Gan, Naili Luo, Cunde Wang
Summary: In this study, a DABCO-promoted cyclization reaction of substituted 2-amino-4H-chromen-4-ones with substituted 2,6-dibenzylidenecyclohexan-1-ones was investigated. Under mild conditions, this reaction provided a novel and efficient access to the 7,8,9,10tetrahydro-12H-chromeno[2,3-b]quinolin-12-ones in good yields, with predominantly E-selective exocyclic double bond.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Hongling Wang, Qiangqiang Zhang, Shuai Xiao, Guanjie Wang, Xuan Huang, Xingkuan Chen, Junmin Zhang
Summary: We have developed a N-heterocyclic carbene (NHC) and base-mediated [3 + 3] annulation reaction for the synthesis of enantioselective dihydropyrano[3,2-b]indoles. Easily prepared sulfonium salts were used as precursors and reacted with unsaturated acyl azolium to achieve this transformation. The reaction conditions are mild and result in privileged indole-fused dihydropyranones with moderate to good yields and excellent enantioselectivities.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Biochemistry & Molecular Biology
R. Alan Aitken, Lynn A. A. Power, Alexandra M. Z. Slawin
Summary: (2S,5S)-5-Phenyl-2-t-butyl-1,3-dioxolan-4-one, derived from mandelic acid, can undergo Michael addition reactions with butenolide and 4-methoxy-beta-nitrostyrene, with the absolute configuration of the products confirmed by X-ray diffraction. Thermal fragmentation of the dioxolanone in these reactions results in the formation of phenyl ketone and chiral epoxy ketone, demonstrating its role as a chiral benzoyl anion equivalent and chiral ketene equivalent, respectively. Additionally, the Diels-Alder cycloaddition chemistry of (2S)-5-methylene-2-t-butyl-1,3-dioxolan-4-one, derived from lactic acid, has been studied, and the X-ray structures of four adducts have been determined, providing insights into the mechanism of dioxolanone fragmentation.
Article
Chemistry, Organic
Yang Chen, Geng-Xie Li, Ai-Qing Peng, Yong Tang, Lijia Wang
Summary: In this study, enantioenriched benzofurochromanes were rapidly constructed through the catalytic [3 + 2] annulation of gamma-chromenes with quinones using a highly efficient chiral SaBOX/copper(II) catalyst system, resulting in high yields (up to 96%) and enantioselectivities (up to 97% ee).
Article
Chemistry, Multidisciplinary
Nan-Nan Mo, Yu-Hang Miao, Xiao Xiao, Yuan-Zhao Hua, Min-Can Wang, Lihua Huang, Guang-Jian Mei
Summary: In this study, the chiral phosphoric acid-catalyzed asymmetric intermolecular formal [3+2] cycloaddition of azoalkenes with azlactones has been achieved, leading to the facile and highly enantioselective construction of a wide range of fully substituted 4-pyrrolin-2-ones with a fully substituted carbon atom in good yields and excellent enantioselectivities.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Ramalingam Boobalan, Rong-Jie Chein
Summary: The emergence of second-generation sulfur-stabilized borenium cations by halophilic Lewis acid SnCl4 results in highly active chiral Lewis acids that are effective catalysts for [4 + 2] cycloaddition, exhibiting excellent enantioselectivity for a variety of substrates and demonstrating good catalytic efficiency.
Article
Chemistry, Organic
Wenxuan Zhang, Jiaying Sun, Zhendong Lian, Ran Song, Daoshan Yang, Jian Lv
Summary: Here, we report a chiral catalyst-catalyzed asymmetric reaction between 2-alkynyphenols and aromatic ethers. The reaction shows high yield and excellent enantioselectivity.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Aurapat Ngamnithiporn, Padon Chuentragool, Poonsakdi Ploypradith, Somsak Ruchirawat
Summary: The development of an intermolecular aza-Diels-Alder (DA) cycloaddition of sultines and imines has been reported. This reaction provides a wide variety of 3-aryl tetrahydroisoquinolines in moderate to excellent yield (up to 89%) by exploiting sultines as o-quinodimethane precursors and aryl imines as dienophiles in the presence of Cu(OTf)(2). The synthetic utility of these products was demonstrated in the preparation of tetracyclic N-heterocycles, including a tetrahydroprotoberberine skeleton.
