1
|
Mandal N, Mondal P, Mandal S, Datta A. Unlocking Enantioselectivity: Synergy of 2-Pyridone and Chiral Amino Acids in Pd-Catalyzed β-C(sp 3)-H Transformations. J Org Chem 2024; 89:9223-9232. [PMID: 38885175 DOI: 10.1021/acs.joc.4c00078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Enantioselective C(sp3)-H activation has garnered significant attention in synthetic and computational chemistry. Chiral transient directing groups (TDGs) hold promise for enabling Pd(II)-catalyzed enantioselective C(sp3)-H functionalization. Despite the interest in this strategy, it presents a challenge because the stereogenic center on the chiral TDG is frequently distant from the C-H bond, leading to a mixture of functionalized products. Our computational study on Pd(II)-catalyzed enantioselective β-C(sp3)-H arylation of aliphatic ketone with chiral amino acids provides a sustainable route to synthesizing complex chiral molecular scaffolds. The cooperative action of 2-pyridone derivatives and chiral amino acids is crucial in promoting the enantio-discriminating C-H activation, oxidative addition, and reductive elimination steps. Using 5-nitro-2-pyridone as the optimal external ligand demonstrates its ability to achieve the highest level of enantioselection. In contrast, the modeled 3,5-di((trifluoromethyl)sulfonyl)-2-pyridone ligand facilitates the most straightforward C-H activation. This study underscores the pivotal role of the alkyl substituent at the α-position of the amino acid (TDG) in altering enantioselectivity.
Collapse
Affiliation(s)
- Nilangshu Mandal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & B Raja S C Mullick Road, Kolkata 700032, India
| | - Partha Mondal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & B Raja S C Mullick Road, Kolkata 700032, India
| | - Sucharita Mandal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & B Raja S C Mullick Road, Kolkata 700032, India
| | - Ayan Datta
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & B Raja S C Mullick Road, Kolkata 700032, India
| |
Collapse
|
2
|
Shlapakov NS, Kobelev AD, Burykina JV, Cheng YZ, You SL, Ananikov VP. Sulfur in Waste-Free Sustainable Synthesis: Advancing Carbon-Carbon Coupling Techniques. Angew Chem Int Ed Engl 2024; 63:e202402109. [PMID: 38421344 DOI: 10.1002/anie.202402109] [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: 01/30/2024] [Revised: 02/29/2024] [Accepted: 02/29/2024] [Indexed: 03/02/2024]
Abstract
This review explores the pivotal role of sulfur in advancing sustainable carbon-carbon (C-C) coupling reactions. The unique electronic properties of sulfur, as a soft Lewis base with significant mesomeric effect make it an excellent candidate for initiating radical transformations, directing C-H-activation, and facilitating cycloaddition and C-S bond dissociation reactions. These attributes are crucial for developing waste-free methodologies in green chemistry. Our mini-review is focused on existing sulfur-directed C-C coupling techniques, emphasizing their sustainability and comparing state-of-the-art methods with traditional approaches. The review highlights the importance of this research in addressing current challenges in organic synthesis and catalysis. The innovative use of sulfur in photocatalytic, electrochemical and metal-catalyzed processes not only exemplifies significant advancements in the field but also opens new avenues for environmentally friendly chemical processes. By focusing on atom economy and waste minimization, the analysis provides broad appeal and potential for future developments in sustainable organic chemistry.
Collapse
Affiliation(s)
- Nikita S Shlapakov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect, 47, 119991, Moscow, Russia
| | - Andrey D Kobelev
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect, 47, 119991, Moscow, Russia
| | - Julia V Burykina
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect, 47, 119991, Moscow, Russia
| | - Yuan-Zheng Cheng
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, 200032, Shanghai, China
| | - Shu-Li You
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, 200032, Shanghai, China
| | - Valentine P Ananikov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect, 47, 119991, Moscow, Russia
| |
Collapse
|
3
|
Rummel L, Schreiner PR. Advances and Prospects in Understanding London Dispersion Interactions in Molecular Chemistry. Angew Chem Int Ed Engl 2024; 63:e202316364. [PMID: 38051426 DOI: 10.1002/anie.202316364] [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: 10/29/2023] [Revised: 12/03/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023]
Abstract
London dispersion (LD) interactions are the main contribution of the attractive part of the van der Waals potential. Even though LD effects are the driving force for molecular aggregation and recognition, the role of these omnipresent interactions in structure and reactivity had been largely underappreciated over decades. However, in the recent years considerable efforts have been made to thoroughly study LD interactions and their potential as a chemical design element for structures and catalysis. This was made possible through a fruitful interplay of theory and experiment. This review highlights recent results and advances in utilizing LD interactions as a structural motif to understand and utilize intra- and intermolecularly LD-stabilized systems. Additionally, we focus on the quantification of LD interactions and their fundamental role in chemical reactions.
Collapse
Affiliation(s)
- Lars Rummel
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| |
Collapse
|
4
|
Bhavyesh D, Soliya S, Konakanchi R, Begari E, Ashalu KC, Naveen T. The Recent Advances in Iron-Catalyzed C(sp 3 )-H Functionalization. Chem Asian J 2023:e202301056. [PMID: 38149480 DOI: 10.1002/asia.202301056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 12/28/2023]
Abstract
The use of iron as a core metal in catalysis has become a research topic of interest over the last few decades. The reasons are clear. Iron is the most abundant transition metal on Earth's crust and it is widely distributed across the world. It has been extracted and processed since the dawn of civilization. All these features render iron a noncontaminant, biocompatible, nontoxic, and inexpensive metal and therefore it constitutes the perfect candidate to replace noble metals (rhodium, palladium, platinum, iridium, etc.). Moreover, direct C-H functionalization is one of the most efficient strategies by which to introduce new functional groups into small organic molecules. The majority of organic compounds contain C(sp3 )-H bonds. Given the enormous importance of organic molecules in so many aspects of existence, the utilization and bioactivity of C(sp3 )-H bonds are of the utmost importance. This review sheds light on the substrate scope, selectivity, benefits, and limitations of iron catalysts for direct C(sp3 )-H bond activations. An overview of the use of iron catalysis in C(sp3 )-H activation protocols is summarized herein up to 2022.
Collapse
Affiliation(s)
- Desai Bhavyesh
- Department of Chemistry, Sardar Vallabhbhai National Institute of Technology Surat, Gujarat, 395 007, India
| | - Sudha Soliya
- Department of Chemistry, Sardar Vallabhbhai National Institute of Technology Surat, Gujarat, 395 007, India
| | - Ramaiah Konakanchi
- Department of Chemistry, VNR Vignana Jyoti Institute of Engineering and Technology, Hyderabad, 500090, India
| | - Eeshwaraiah Begari
- School of Applied Material Sciences, Central University of Gujarat, Gandhinagar, 382030, India
| | - Kashamalla Chinna Ashalu
- Department of Chemistry, School of Science, Indrashil University, Rajpur, Kadi, Gujarat, 382715, India
| | - Togati Naveen
- Department of Chemistry, Sardar Vallabhbhai National Institute of Technology Surat, Gujarat, 395 007, India
| |
Collapse
|
5
|
Strassfeld DA, Chen CY, Park HS, Phan DQ, Yu JQ. Hydrogen-bond-acceptor ligands enable distal C(sp 3)-H arylation of free alcohols. Nature 2023; 622:80-86. [PMID: 37674074 PMCID: PMC11139439 DOI: 10.1038/s41586-023-06485-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 07/26/2023] [Indexed: 09/08/2023]
Abstract
The functionalization of C-H bonds in organic molecules is one of the most direct approaches for chemical synthesis. Recent advances in catalysis have allowed native chemical groups such as carboxylic acids, ketones and amines to control and direct C(sp3)-H activation1-4. However, alcohols, among the most common functionalities in organic chemistry5, have remained intractable because of their low affinity for late transition-metal catalysts6,7. Here we describe ligands that enable alcohol-directed arylation of δ-C(sp3)-H bonds. We use charge balance and a secondary-coordination-sphere hydrogen-bonding interaction-evidenced by structure-activity relationship studies, computational modelling and crystallographic data-to stabilize L-type hydroxyl coordination to palladium, thereby facilitating the assembly of the key C-H cleavage transition state. In contrast to previous studies in C-H activation, in which secondary interactions were used to control selectivity in the context of established reactivity8-13, this report demonstrates the feasibility of using secondary interactions to enable challenging, previously unknown reactivity by enhancing substrate-catalyst affinity.
Collapse
Affiliation(s)
| | - Chia-Yu Chen
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Han Seul Park
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - D Quang Phan
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Jin-Quan Yu
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA.
| |
Collapse
|
6
|
Lustosa DM, Milo A. Mechanistic Inference from Statistical Models at Different Data-Size Regimes. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Danilo M. Lustosa
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Anat Milo
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| |
Collapse
|
7
|
Baek D, Ryu H, Hahm H, Lee J, Hong S. Palladium Catalysis Featuring Attractive Noncovalent Interactions Enabled Highly Enantioselective Access to β-Quaternary δ-Lactams. ACS Catal 2022. [DOI: 10.1021/acscatal.2c00541] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Doohyun Baek
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Huijeong Ryu
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Hyungwoo Hahm
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| | - Junseong Lee
- Department of Chemistry, Chonnam National University, 77 Yongbong-ro,
Buk-gu, Gwangju 61186, Republic of Korea
| | - Sukwon Hong
- Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, Republic of Korea
| |
Collapse
|
8
|
Liao G, Zhang T, Jin L, Wang BJ, Xu CK, Lan Y, Zhao Y, Shi BF. Experimental and Computational Studies on the Directing Ability of Chalcogenoethers in Palladium-Catalyzed Atroposelective C-H Olefination and Allylation. Angew Chem Int Ed Engl 2022; 61:e202115221. [PMID: 34985788 DOI: 10.1002/anie.202115221] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Indexed: 01/14/2023]
Abstract
We present herein our experimental and DFT computational studies on the directing ability of chalcogenoether motifs in Pd-catalyzed atroposelective C-H functionalization. The thioether motif was found to be a superior directing group compared to the corresponding ether and selenoether in terms of reactivity and enantiocontrol. Remarkably, DFT calculation provided a predictive model for the optimization of reaction conditions and the interpretation of the origin of enantioselectivity. Both Pd-catalyzed enantioselective C-H olefination and allylation reactions were successfully developed using chiral phosphoric acids as efficient ligands, providing a broad range of axially chiral biaryls in good yields with excellent enantioselectivities. The highly enantio- and diastereoselective construction of polyaryls bearing multiple stereogenic axes, gram-scale reaction and various chemical transformations make this protocol more attractive and significant.
Collapse
Affiliation(s)
- Gang Liao
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Tao Zhang
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China
| | - Liang Jin
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Bing-Jie Wang
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Cheng-Kai Xu
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Yu Lan
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.,School of Chemistry and Chemical Engineering, and Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing, 400030, China
| | - Yu Zhao
- Department of Chemistry, National University of Singapore, 117543, Singapore, Singapore
| | - Bing-Feng Shi
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China.,Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.,School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, China
| |
Collapse
|
9
|
Liao G, Zhang T, Jin L, Wang BJ, Xu CK, Lan Y, Zhao Y, Shi BF. Experimental and Computational Studies on the Directing Ability of Chalcogenoethers in Palladium‐Catalyzed Atroposelective C–H Olefination and Allylation. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202115221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Gang Liao
- Zhejiang University Department of Chemistry CHINA
| | - Tao Zhang
- Zhengzhou University Green Catalysis Center, College of Chemistry CHINA
| | - Liang Jin
- Zhejiang University Department of Chemistry CHINA
| | | | - Cheng-Kai Xu
- Zhejiang University Department of Chemistry CHINA
| | - Yu Lan
- Zhengzhou University Green Catalysis Center, College of Chemistry CHINA
| | - Yu Zhao
- National University of Singapore Department of Chemistry SINGAPORE
| | - Bing-Feng Shi
- Zhejiang University Department of Chemistry 38 Zheda Rd. 310027 Hangzhou CHINA
| |
Collapse
|
10
|
Li Y, Liou YC, Chen X, Ackermann L. Thioether-enabled palladium-catalyzed atroposelective C–H olefination for N−C and C−C axial chirality. Chem Sci 2022; 13:4088-4094. [PMID: 35440980 PMCID: PMC8985512 DOI: 10.1039/d2sc00748g] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 03/10/2022] [Indexed: 12/05/2022] Open
Abstract
Thioethers allowed for highly atroposelective C–H olefinations by a palladium/chiral phosphoric acid catalytic system under ambient air. Both N–C and C–C axial chiral (hetero)biaryls were successfully constructed, leading to a broad range of axially chiral N-aryl indoles and biaryls with excellent enantioselectivities up to 99% ee. Experimental and computational studies were conducted to unravel the walking mode for the atroposelective C–H olefination. A plausible chiral induction model for the enantioselectivity-determining step was established by detailed DFT calculations. Thioethers allowed for highly atroposelective C–H olefinations by a palladium/chiral phosphoric acid catalytic system under ambient air.![]()
Collapse
Affiliation(s)
- Yanjun Li
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
| | - Yan-Cheng Liou
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
| | - Xinran Chen
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
- Department of Chemistry, Zhejiang University Hangzhou 310027 China
| | - Lutz Ackermann
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen Tammannstraße 2 37077 Göttingen Germany
| |
Collapse
|
11
|
Wu ZH, Fang DC. DFT study on ruthenium-catalyzed N-methylbenzamide-directed 1,4-addition of the ortho C–H bond to maleimide via C–H/C–C activation. Org Chem Front 2022. [DOI: 10.1039/d2qo01487d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
B3LYP-D3a+IDSCRF/tzp-dkh(-dfg) calculations indicate that CO as a directing group is much more favourable than the N–H group, and the real active catalyst is an ionic type with one [SbF6]− group.
Collapse
Affiliation(s)
- Zi-Hao Wu
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - De-Cai Fang
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| |
Collapse
|
12
|
Wang J, Li M. Recent Advances on Transition-Metal-Catalyzed Asymmetric C–H Arylation Reactions. SYNTHESIS-STUTTGART 2021. [DOI: 10.1055/a-1677-5870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractTransition-metal-catalyzed asymmetric C–H functionalization has become a powerful strategy to synthesize complex chiral molecules. Recently, catalytic enantioselective C–H arylation has attracted great interest from organic chemists to construct aryl-substituted chiral compounds. In this short review, we highlight recent advances in asymmetric C–H arylation from 2019 to late 2021, including enantioselective C(sp2)–H arylation to construct axial or planar chiral compounds, and enantioselective C(sp3)–H arylation to introduce central chirality via desymmetrization of the methyl group or methylene C–H activation. These processes proceed with palladium, rhodium, iridium, nickel, or copper catalysts, and utilize aryl halides, boron, or diazo derivatives as arylation reagents.1 Introduction2 Transition-Metal-Catalyzed Asymmetric C(sp2)–H Arylation2.1 Chelation-Assisted Asymmetric C(sp2)–H Arylation for the Construction of Atropisomer2.2 Chelation-Assisted Asymmetric C(sp2)–H Arylation for the Construction of Planar Chiral Compounds2.3 Chelation-Assisted Asymmetric C(sp2)–H Arylation and Axial-to-Central Chirality Transfer for the Construction of Spirocycles2.4 Other Asymmetric C(sp2)–H Arylation Reactions3 Transition-Metal-Catalyzed Asymmetric C(sp3)–H Arylation3.1 Chelation-Assisted Enantioselective C(sp3)–H Arylation through Desymmetrization3.2 Chelation-Assisted Enantioselective Methylene C(sp3)–H Arylation3.3 Other Asymmetric C(sp3)–H Arylations4 Conclusion and Outlook
Collapse
Affiliation(s)
- Jun Wang
- Department of Chemistry, Southern University of Science and Technology
- Department of Chemistry, Hong Kong Baptist University
| | - Mingliang Li
- Department of Chemistry, Southern University of Science and Technology
| |
Collapse
|
13
|
Du B, Ouyang Y, Chen Q, Yu WY. Thioether-Directed NiH-Catalyzed Remote γ-C(sp 3)-H Hydroamidation of Alkenes by 1,4,2-Dioxazol-5-ones. J Am Chem Soc 2021; 143:14962-14968. [PMID: 34496211 DOI: 10.1021/jacs.1c05834] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A NiH-catalyzed thioether-directed cyclometalation strategy is developed to enable remote methylene C-H bond amidation of unactivated alkenes. Due to the preference for five-membered nickelacycle formation, the chain-walking isomerization initiated by the NiH insertion to an alkene can be terminated at the γ-methylene site remote from the alkene moiety. By employing 2,9-dibutyl-1,10-phenanthroline (L4) as the ligand and dioxazolones as the reagent, the amidation occurs at the γ-C(sp3)-H bonds to afford the amide products in up to 90% yield (>40 examples) with remarkable regioselectivity (up to 24:1 rr).
Collapse
Affiliation(s)
- Bingnan Du
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Yuxin Ouyang
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Qishu Chen
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Wing-Yiu Yu
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| |
Collapse
|