1
|
Wu Z, Li M, Gu Q, You SL. SCpRh(III)-Catalyzed Asymmetric C-H Trifluoromethylalkylation of N-Methoxybenzamides with β-Trifluoromethyl-α,β-Unsaturated Ketones. Org Lett 2024; 26:1501-1505. [PMID: 38349077 DOI: 10.1021/acs.orglett.4c00177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
Asymmetric C-H trifluoromethylalkylation represents a novel and straightforward synthetic method for the construction of chiral CF3-containing compounds. However, the reported examples remain limited, given the challenges of reactivity and enantioselective control. Herein, we report a SCpRh(III)-catalyzed asymmetric aryl and alkenyl C-H trifluoromethylalkylation reaction with β-trifluoromethyl-α,β-unsaturated ketones. The chiral CF3-bearing adducts were obtained in moderate to good yields with high enantioselectivity (up to 81% yield and 96% ee). The reaction features mild conditions and broad substrate scope. The chiral CF3-bearing products could undergo diverse functional group transformations.
Collapse
Affiliation(s)
- Zhuo Wu
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Muzi Li
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Qing Gu
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Shu-Li You
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| |
Collapse
|
2
|
Kim N, Oh W, Knust KN, Zazyki Galetto F, Su X. Molecularly Selective Polymer Interfaces for Electrochemical Separations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:16685-16700. [PMID: 37955994 DOI: 10.1021/acs.langmuir.3c02389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The molecular design of polymer interfaces has been key for advancing electrochemical separation processes. Precise control of molecular interactions at electrochemical interfaces has enabled the removal or recovery of charged species with enhanced selectivity, capacity, and stability. In this Perspective, we provide an overview of recent developments in polymer interfaces applied to liquid-phase electrochemical separations, with a focus on their role as electrosorbents as well as membranes in electrodialysis systems. In particular, we delve into both the single-site and macromolecular design of redox polymers and their use in heterogeneous electrochemical separation platforms. We highlight the significance of incorporating both redox-active and non-redox-active moieties to tune binding toward ever more challenging separations, including structurally similar species and even isomers. Furthermore, we discuss recent advances in the development of selective ion-exchange membranes for electrodialysis and the critical need to control the physicochemical properties of the polymer. Finally, we share perspectives on the challenges and opportunities in electrochemical separations, ranging from the need for a comprehensive understanding of binding mechanisms to the continued innovation of electrochemical architectures for polymer electrodes.
Collapse
Affiliation(s)
- Nayeong Kim
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Wangsuk Oh
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Kyle N Knust
- Department of Chemistry, Millikin University, 1184 W. Main Street, Decatur, Illinois 62522, United States
| | - Fábio Zazyki Galetto
- Departamento de Química, Universidade Federal de Santa Catarina (UFSC), Florianopolis SC 88040-900, Brazil
| | - Xiao Su
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
3
|
Kuang X, Li JJ, Liu T, Ding CH, Wu K, Wang P, Yu JQ. Cu-mediated enantioselective C-H alkynylation of ferrocenes with chiral BINOL ligands. Nat Commun 2023; 14:7698. [PMID: 38001060 PMCID: PMC10673954 DOI: 10.1038/s41467-023-43278-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
A wide range of Cu(II)-catalyzed C-H activation reactions have been realized since 2006, however, whether a C-H metalation mechanism similar to Pd(II)-catalyzed C-H activation reaction is operating remains an open question. To address this question and ultimately develop ligand accelerated Cu(II)-catalyzed C-H activation reactions, realizing the enantioselective version and investigating the mechanism is critically important. With a modified chiral BINOL ligand, we report the first example of Cu-mediated enantioselective C-H activation reaction for the construction of planar chiral ferrocenes with high yields and stereoinduction. The key to the success of this reaction is the discovery of a ligand acceleration effect with the BINOL-based diol ligand in the directed Cu-catalyzed C-H alkynylation of ferrocene derivatives bearing an oxazoline-aniline directing group. This transformation is compatible with terminal aryl and alkyl alkynes, which are incompatible with Pd-catalyzed C-H activation reactions. This finding provides an invaluable mechanistic information in determining whether Cu(II) cleaves C-H bonds via CMD pathway in analogous manner to Pd(II) catalysts.
Collapse
Affiliation(s)
- Xin Kuang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, CAS 345 Lingling Road, Shanghai, 200032, P.R. China
- School of Science, Shanghai University, 99 Shang-Da Road, Shanghai, 200444, P. R. China
| | - Jian-Jun Li
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, CAS 345 Lingling Road, Shanghai, 200032, P.R. China
| | - Tao Liu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, CAS 345 Lingling Road, Shanghai, 200032, P.R. China
| | - Chang-Hua Ding
- School of Science, Shanghai University, 99 Shang-Da Road, Shanghai, 200444, P. R. China
| | - Kevin Wu
- The Scripps Research Institute (TSRI), 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Peng Wang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, CAS 345 Lingling Road, Shanghai, 200032, P.R. China.
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, P.R. China.
| | - Jin-Quan Yu
- The Scripps Research Institute (TSRI), 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.
| |
Collapse
|
4
|
Liu CX, Yin SY, Zhao F, Yang H, Feng Z, Gu Q, You SL. Rhodium-Catalyzed Asymmetric C-H Functionalization Reactions. Chem Rev 2023; 123:10079-10134. [PMID: 37527349 DOI: 10.1021/acs.chemrev.3c00149] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
This review summarizes the advancements in rhodium-catalyzed asymmetric C-H functionalization reactions during the last two decades. Parallel to the rapidly developed palladium catalysis, rhodium catalysis has attracted extensive attention because of its unique reactivity and selectivity in asymmetric C-H functionalization reactions. In recent years, Rh-catalyzed asymmetric C-H functionalization reactions have been significantly developed in many respects, including catalyst design, reaction development, mechanistic investigation, and application in the synthesis of complex functional molecules. This review presents an explicit outline of catalysts and ligands, mechanism, the scope of coupling reagents, and applications.
Collapse
Affiliation(s)
- Chen-Xu Liu
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, P. R. China
| | - Si-Yong Yin
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, P. R. China
| | - Fangnuo Zhao
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, P. R. China
| | - Hui Yang
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, P. R. China
| | - Zuolijun Feng
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, P. R. China
| | - Qing Gu
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, P. R. China
| | - Shu-Li You
- New Cornerstone Science Laboratory, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, P. R. China
| |
Collapse
|
5
|
Zhu X, Wu H, Wang Y, Huang G, Wang F, Li X. Rhodium-catalyzed annulative approach to N-N axially chiral biaryls via C-H activation and dynamic kinetic transformation. Chem Sci 2023; 14:8564-8569. [PMID: 37592987 PMCID: PMC10430736 DOI: 10.1039/d3sc02800c] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 07/13/2023] [Indexed: 08/19/2023] Open
Abstract
N-N axially chiral biaryls represent a rarely explored class of atropisomeric compounds. We hereby report rhodium-catalyzed enantioselective [4 + 2] oxidative annulation of internal alkynes with benzamides bearing two classes of N-N directing groups. The coupling occurs under mild conditions via NH and CH annulation through the dynamic kinetic transformation of the directing group and is highly enantioselective with good functional tolerance. Computational studies of a coupling system at the DFT level has been conducted, and the alkyne insertion was identified as the enantio-determining as well as the turnover-limiting step.
Collapse
Affiliation(s)
- Xiaohan Zhu
- School of Chemistry and Chemical Engineering, Shaanxi Normal University Xi'an 710062 China
| | - Hongli Wu
- Department of Chemistry, School of Science and Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Tianjin University Tianjin 300072 China
| | - Yishou Wang
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Sciences, Shandong University Qingdao 266237 China
| | - Genping Huang
- Department of Chemistry, School of Science and Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Tianjin University Tianjin 300072 China
| | - Fen Wang
- School of Chemistry and Chemical Engineering, Shaanxi Normal University Xi'an 710062 China
| | - Xingwei Li
- School of Chemistry and Chemical Engineering, Shaanxi Normal University Xi'an 710062 China
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Sciences, Shandong University Qingdao 266237 China
| |
Collapse
|
6
|
Zhang M, Zhao P, Liu Q, Liu X, Hu J, Wu D, Liu L. Construction of N-Ferrocene Substituted Benzodihydrooxazoles via a Catalyst-Free Aza-Michael Addition/C(sp 3)-O Bond Formation Tandem Reaction. Molecules 2023; 28:5615. [PMID: 37513488 PMCID: PMC10384804 DOI: 10.3390/molecules28145615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 07/21/2023] [Accepted: 07/23/2023] [Indexed: 07/30/2023] Open
Abstract
A catalyst-free aza-Michael addition/C(sp3)-O bond formation tandem reaction of substituted amino ferrocenes with quinone esters was developed, which provided a green and efficient strategy for the construction of a C(sp3)-O bond from C(sp3)-H, and a series of N-ferrocene-substituted benzodihydrooxazoles were smoothly produced in moderate to excellent yields (up to >99% yield). The mechanism experiments showed that quinone esters performed as both substrate and oxidant. The salient features of this transformation include good functional group tolerance, broad substrate scope and mild conditions.
Collapse
Affiliation(s)
- Mingliang Zhang
- Henan Engineering Research Center of Green Synthesis for Pharmaceuticals, School of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000, China
| | - Pin Zhao
- College of Chemistry, Zhengzhou University, Zhengzhou 450052, China
| | - Qilv Liu
- Henan Engineering Research Center of Green Synthesis for Pharmaceuticals, School of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000, China
| | - Xinlei Liu
- Henan Engineering Research Center of Green Synthesis for Pharmaceuticals, School of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000, China
| | - Jingya Hu
- Henan Engineering Research Center of Green Synthesis for Pharmaceuticals, School of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000, China
| | - Dongqing Wu
- Henan Engineering Research Center of Green Synthesis for Pharmaceuticals, School of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000, China
| | - Lantao Liu
- Henan Engineering Research Center of Green Synthesis for Pharmaceuticals, School of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000, China
- College of Chemistry, Zhengzhou University, Zhengzhou 450052, China
| |
Collapse
|
7
|
Cobalt(III)-catalyzed asymmetric ring-opening of 7-oxabenzonorbornadienes via indole C-H functionalization. Nat Commun 2023; 14:1094. [PMID: 36841798 PMCID: PMC9968317 DOI: 10.1038/s41467-023-36723-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 02/13/2023] [Indexed: 02/26/2023] Open
Abstract
Asymmetric ring-opening of 7-oxabenzonorbornadienes is achieved via Co-catalyzed indole C-H functionalization. The utilization of chiral Co-catalyst consisting of a binaphthyl-derived trisubstituted cyclopentadienyl ligand resulted in high yields (up to 99%) and excellent enantioselectivity (>99% ee) for the target products with tolerance for diverse functional groups. Opposite diastereoselectivities are obtained with chiral Co-catalyst or Cp*CoI2CO. Combined experimental and computational studies suggest β-oxygen elimination being the selectivity-determining step of the reaction. Meanwhile, the reactions of 7-azabenzonorbornadiene could also be executed in a diastereodivergent manner.
Collapse
|
8
|
Zhang WW, Wang Q, Zhang SZ, Zheng C, You SL. (SCp)Rhodium-Catalyzed Asymmetric Satoh-Miura Reaction for Building-up Axial Chirality: Counteranion-Directed Switching of Reaction Pathways. Angew Chem Int Ed Engl 2023; 62:e202214460. [PMID: 36383091 DOI: 10.1002/anie.202214460] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/12/2022] [Accepted: 11/16/2022] [Indexed: 11/17/2022]
Abstract
Satoh-Miura reaction is an important method for extending π-systems by forging multi-substituted benzene rings via double aryl C-H activation and annulation with alkynes. However, the development of highly enantioselective Satoh-Miura reaction remains rather challenging. Herein, we report an asymmetric Satoh-Miura reaction between 1-aryl benzo[h]isoquinolines and internal alkynes enabled by a SCpRh-catalyst. Judiciously choosing the counteranion of the Rh-catalyst is crucial for the desired reactivity over the competitive formation of azoniahelicenes. Detailed mechanistic studies support the proposal of counteranion-directed switching of reaction pathways in Rh-catalyzed asymmetric C-H activation.
Collapse
Affiliation(s)
- Wen-Wen Zhang
- Chang-Kung Chuang Institute, East China Normal University, 3663 N. Zhongshan Road, Shanghai, 200062, China.,State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China
| | - Qiang Wang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China
| | - Su-Zhen Zhang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China
| | - Chao Zheng
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China
| | - Shu-Li You
- Chang-Kung Chuang Institute, East China Normal University, 3663 N. Zhongshan Road, Shanghai, 200062, China.,State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China
| |
Collapse
|
9
|
Peluso P, Mamane V. Ferrocene derivatives with planar chirality and their enantioseparation by liquid-phase techniques. Electrophoresis 2023; 44:158-189. [PMID: 35946562 PMCID: PMC10087518 DOI: 10.1002/elps.202200148] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 02/01/2023]
Abstract
In the last decade, planar chiral ferrocenes have attracted a growing interest in several fields, particularly in asymmetric catalysis, medicinal chemistry, chiroptical spectroscopy and electrochemistry. In this frame, the access to pure or enriched enantiomers of planar chiral ferrocenes has become essential, relying on the availability of efficient asymmetric synthesis procedures and enantioseparation methods. Despite this, in enantioseparation science, these metallocenes were not comprehensively explored, and very few systematic analytical studies were reported in this field so far. On the other hand, enantioselective high-performance liquid chromatography has been frequently used by organic and organometallic chemists in order to measure the enantiomeric purity of planar chiral ferrocenes prepared by asymmetric synthesis. On these bases, this review aims to provide the reader with a comprehensive overview on the enantioseparation of planar chiral ferrocenes by discussing liquid-phase enantioseparation methods developed over time, integrating this main topic with the most relevant aspects of ferrocene chemistry. Thus, the main structural features of ferrocenes and the methods to model this class of metallocenes will be briefly summarized. In addition, planar chiral ferrocenes of applicative interest as well as the limits of asymmetric synthesis for the preparation of some classes of planar chiral ferrocenes will also be discussed with the aim to orient analytical scientists towards 'hot topics' and issues which are still open for accessing enantiomers of ferrocenes featured by planar chirality.
Collapse
Affiliation(s)
- Paola Peluso
- Istituto di Chimica Biomolecolare ICB CNR, Sede secondaria di Sassari, Sassari, Italy
| | - Victor Mamane
- Institut de Chimie de Strasbourg, UMR 7177, CNRS-Université de Strasbourg, Strasbourg, France
| |
Collapse
|
10
|
Mou Q, Zhao R, Sun B. Recent Advances in Transition-Metal-Catalyzed C-H Functionalization of Ferrocene Amides. Chem Asian J 2022; 17:e202200818. [PMID: 36047433 DOI: 10.1002/asia.202200818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/30/2022] [Indexed: 11/11/2022]
Abstract
During the past decades, in synthetic organic chemistry, directing-group-assisted C-H functionalization is found to be a key tool for the expedient and site-selective construction of C-C and hybrid bonds. Among C-H functionalization of ferrocene derivatives, the directed group strategy is undoubtedly the most commonly used method. Compared to the other directing groups, ferrocene amides can be synthesized easily and are now recognized as one of the most efficient devices for the selective functionalization of certain positions because its metal centre permits fine, tuneable and reversible coordination. The family of amide directing groups mainly comprises monodentate and bidentate directing groups, which are categorized on the basis of coordination sites. In this review, various C-H bond functionalization reactions of ferrocene using amide directing groups are broadly discussed.
Collapse
Affiliation(s)
- Qi Mou
- Qingdao University of Science and Technology, College of Chemical Engineering, CHINA
| | - Ruyuan Zhao
- Qingdao University of Science and Technology, College of Chemical Engineering, CHINA
| | - Bo Sun
- Qingdao University of Science and Technology, college of chemical engineering, zhengzhoulu No. 53, 266000, Qingdao, CHINA
| |
Collapse
|
11
|
Li H, Luo H, Ban Y, Wang Y, Li D, Yang J. Thioamide‐Directed Transition‐metal‐catalyzed C(sp2) –H bond vinylation and arylation of Ferrocenes. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Hao Li
- Ningxia University State Key Laboratory of High Efficiency Utilization of Coal and Green Chemical Engineering CHINA
| | - Hui Luo
- Ningxia University State Key Laboratory of High Efficiency Utilization of Coal and Green Chemical Engineering CHINA
| | - Yan Ban
- Ningxia University State Key Laboratory of High Efficiency Utilization of Coal and Green Chemical Engineering CHINA
| | | | | | | |
Collapse
|