Article
Chemistry, Multidisciplinary
Alena Budinska, Helma Wennemers
Summary: This article presents a mild and efficient organocatalytic method for the stereoselective synthesis of chiral triflones using alpha-aryl vinyl triflones, previously unexplored in asymmetric synthesis. The products can be easily derivatized into disubstituted delta-sultones, gamma-lactones, and pyrrolidine heterocycles, highlighting their synthetic versatility.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Organic
Fengyun Gao, Boyu Li, Yalan Wang, Qushuo Chen, Yongzhen Li, Kairong Wang, Wenjin Yan
Summary: This review summarizes routine asymmetric synthetic methods for the effective and selective introduction of difluoromethyl groups into desired compounds, which is valuable for the synthesis of fluorine-containing compounds and for modulating the properties of organic compounds in drug design.
ORGANIC CHEMISTRY FRONTIERS
(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
Qing-Xian Xie, Li-Xia Liu, Zhou-Hao Zhu, Chang-Bin Yu, Yong-Gui Zhou
Summary: In this study, a ruthenium-catalyzed asymmetric transfer hydrogenation of 2,3-disubstituted flavanones was developed. The reaction allowed for the construction of three contiguous stereocenters under basic conditions through a combination of dynamic kinetic resolution and retro-oxa-Michael addition. This method provided chiral flavanols with excellent enantioselectivities and diastereoselectivities.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Bin Mao, Zhi-Wei Chen, Jian-Fei Wang, Chao-Huan Zhang, Zhi-Qian Du, Chuan-Ming Yu
Summary: In this study, the enantioselective organocatalytic conjugate alkenylation of fi-substituted alkenyl benzimidazoles was achieved, leading to the formation of beta-stereogenic 2-alkyl benzimidazole derivatives with excellent enantio-selectivities. Chiral binaphthols were found to be effective catalysts for promoting the nucleophilic addition of bench-stable alkenyl trifluoroborate salts under mild conditions. By utilizing C=N-containing azaarenes as activating groups, the applications of these catalysts were expanded. The synthetic utility of this strategy was demonstrated by converting the products into several useful enantiomerically enriched benzimidazole building blocks.
Article
Chemistry, Multidisciplinary
Nina F. C. Ritchie, Adam J. Zahara, Sidney M. Wilkerson-Hill
Summary: In this study, we report the divergent reactivity of 2,2-dialkyl-3-(E)-alkenyl N-tosylhydrazones under Pd-catalyzed cross-coupling conditions, enabling the Z-selective synthesis of 3-aryl-1,4-dienes and gem-dialkyl vinylcyclopropanes. We found that the dialkylbiaryl phosphine ligand SPhos was the optimal ligand, producing skipped dienes with up to 83% isolated yield. The ratio of skipped diene to vinylcyclopropane depends on the structure of the alpha,alpha-disubstituted hydrazones and the aryl halide partner. Using sterically encumbered aryl bromides selectively provided trans-cyclopropane products with yields up to 69%. The reaction is stereospecific and stereoselective and occurs alongside a competing 1,2-alkenyl group migration pathway.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Kun Jiang, Shi-Jun Li, Qing-Peng Liu, Ning Yu, Yu-Lin Li, Yu-Qiang Zhou, Kui-Cheng He, Jing Lin, Ting-Yu Zheng, Jian Lang, Yu Lan, Ye Wei
Summary: Bridged tetracyclic nitrogen scaffolds are commonly found in biologically active molecules and medicinally relevant structures. Traditional methods require complex reaction steps and/or specific starting materials. This study presents an unprecedented iminyl radical-triggered relay annulation from oxime-derived peresters and azadienes, which demonstrates good substrate scope, functional group compatibility, and the ability to deliver various bridged aza-tetracyclic compounds with complex molecular topology and four contiguous stereogenic centers in a single operation.
Article
Chemistry, Physical
Li-Xia Liu, Wen-Jun Huang, Qing-Xian Xie, Bo Wu, Chang-Bin Yu, Yong-Gui Zhou
Summary: The research proposed a new strategy for dynamic kinetic resolution, successfully achieving enantioselective separation of flavonoid compounds and forming two stereogenic centers, providing a new way for organic synthesis.
Article
Chemistry, Applied
Qingyu Yin, Zhiming Li, Fan Wu, Mingtong Ji, Chao Fu, Xiaoyu Wu
Summary: A diastereoselective and enantioselective conjugate addition of alpha-substituted acyl imidazole to nitroalkene catalyzed by nickel bisoxazoline complex and B(C6F5)(3) has been developed. The reaction showed broad substrate tolerance and high yields and enantioselectivity. The coordination catalyst and co-catalyst played a crucial role in the success of the reaction.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Physical
Xiaodong Tang, Chuan Xiang Alvin Tan, Wai-Lun Chan, Fuhao Zhang, Wenrui Zheng, Yixin Lu
Summary: In this study, we introduced a new type of allenic ketone as a dielectrophilic C4 synthon in phosphine-mediated reactions, enabling a highly enantioselective [4 + 2] annulation. This strategy allowed for the facile creation of spirocyclic bisindoline structures containing two contiguous quaternary stereogenic centers. Synthetic manipulations of the [4 + 2] annulation product led to concise total synthesis of (-)-folicanthine.
Article
Chemistry, Organic
Kazuki Fujita, Momona Hattori, Tsunayoshi Takehara, Takeyuki Suzuki, Shuichi Nakamura
Summary: The enantioselective reaction of a-substituted ig-nitroacrylates with oxazol-5-(4H)-ones (oxazolones) to construct consecutive tetrasubstituted stereogenic centers was achieved. A cinchona alkaloid sulfonamide catalyst provided products with vicinal chiral centers that exhibited excellent enantio- and diastereoselectivities. The obtained products were further transformed into different chiral compounds without compromising their enantiopurity. Moreover, density functional theory (DFT) calculations were employed to elucidate the mechanism and origin of the observed stereoselectivity of the reaction.
Article
Chemistry, Physical
Ying Wang, JianJun Yin, Yanfei Li, Xiuping Yuan, Tao Xiong, Qian Zhang
Summary: We report the successful copper-catalyzed asymmetric conjugate addition of beta-substituted alkenyl heteroarenes, one of the most challenging Michael acceptors, with alkenes. This method enables the synthesis of diverse chiral heteroarenes with good to excellent yields and excellent enantioselectivity. Moreover, the Michael addition products can be further transformed into valuable acyclic enantioenriched structures through chiral amine catalysis. Mechanistic studies suggest that the hydrocupration step may be the turnover-limiting step, and control experiments provide insights into the preferential alkene hydrocupration in the presence of beta-substituted alkenyl heteroarenes and the Ph-BPE-ligated CuH catalyst.
Article
Chemistry, Multidisciplinary
Zhi-Zhou Pan, Deng Pan, Jia-Heng Li, Xiao-Song Xu, Liang Yin
Summary: Chiral azaarene compounds are synthesized through a copper(I)-catalyzed asymmetric conjugate addition reaction with (E)-beta-substituted alkenyl azaarenes as the substrate. The reaction shows good yields, Z/E ratios, and enantioselectivity. Various azaarenes can be used as substrates, and specific product outcomes depend on the configuration of the starting unsaturated azaarenes. DFT calculations provide insights into the selectivity-determining step and the origin of selectivities. The synthesized compounds have synthetic utility in various transformations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Binghao Liu, Jing Qi, Yatong Wu, Jia-Hui Li, Yanting Li, Xiao-Yong Duan
Summary: In this work, an efficient strategy for the construction of dimeric spirocyclic bisindoline alkaloid derivatives was introduced using NHC-catalyzed enantioselective [3 + 2] annulation of enals with isoindigo. The reaction successfully constructs three contiguous stereogenic centers, including two congested all-carbon quaternary stereogenic centers, in a simple one-step operation.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Arko Das, Harshit Joshi, Vinod K. Singh
Summary: An enantioselective approach for synthesizing fluorinated azaarenes with vicinal quaternary-tertiary stereocenters has been summarized, utilizing a chiral copper(I)-phosphine complex to bind with the azaarenes followed by Michael addition to unsaturated acyl imidazoles, resulting in highly enantioselective compounds with excellent yields. Further functionalization of the acyl imidazole part has also been demonstrated.
