1
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Gorad SS, Ghorai P. Organocatalytic Desymmetric Double Aza-Michael Addition Cascade: Enantioselective Synthesis of Fused Morpholines. Org Lett 2024; 26:5571-5576. [PMID: 38921656 DOI: 10.1021/acs.orglett.4c01988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
Double aza-Michael addition (DAM) has become an emerging strategy for the construction of two carbon-nitrogen bonds in a single step, which can significantly simplify the synthesis of N-heterocycles. Hitherto, their asymmetric catalytic genre remains unattempted. Herein, we describe the judicious design of an organocatalytic enantioselective desymmetric double aza-Michael addition cascade to access a series of functionalized fused morpholines with excellent yields and diastereo- and enantioselectivities. A one-pot telescopic synthesis was demonstrated for a bridged triheterocyclic compound. In addition, scale-up synthesis and various attractive postsynthetic modifications of the title products amplify the significance of the current methodology.
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Affiliation(s)
- Sachin S Gorad
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal-462066, India
| | - Prasanta Ghorai
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal-462066, India
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2
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Hu T, Zhao Y, Luo X, Li Z, Yang WL. Brønsted acid catalyzed [4 + 2] cycloaddition for the synthesis of bisbenzannulated spiroketals with antifungal activities. Org Biomol Chem 2024; 22:4656-4661. [PMID: 38804023 DOI: 10.1039/d4ob00584h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The intermolecular [4 + 2] cycloaddition of o-hydroxy benzyl alcohols with isochroman ketals was realized by CF3CO2H catalysis. A broad range of bisbenzannulated [6,6]-spiroketals were formed under the metal-free mild conditions in moderate to excellent yields (45-98%) with mostly excellent diastereoselectivities (up to >20 : 1 dr). Furthermore, the enantioselective version was also preliminarily investigated and the bisbenzannulated [6,6]-spiroketal was obtained with 61% ee in the presence of Sc(OTf)3/Feng's chiral N,N'-dioxide ligand. Some of the bisbenzannulated [6,6]-spiroketal products showed good in vitro antifungal activities against Sclerotinia sclerotiorum and Rhizoctonia solani.
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Affiliation(s)
- Teng Hu
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China.
| | - Yuxuan Zhao
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China.
| | - Xiaoyan Luo
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China.
| | - Zhong Li
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China.
| | - Wu-Lin Yang
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China.
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3
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Gayen P, Sar S, Ghorai P. Stereodivergent Synthesis of Spiroaminals via Chiral Bifunctional Hydrogen Bonding Organocatalysis. Angew Chem Int Ed Engl 2024; 63:e202404106. [PMID: 38563755 DOI: 10.1002/anie.202404106] [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: 02/28/2024] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 04/04/2024]
Abstract
Spiroaminals represent novel structural motifs prevalent in diverse natural products and biologically active molecules. Achieving their enantioselective synthesis is a highly desirable and challenging task in synthetic endeavors due to their intricate molecular frameworks. Herein, we accomplished the first stereodivergent construction of spiroaminals using chiral bifunctional organocatalyzed intramolecular 1,2-addition followed by an oxa-Michael addition cascade in a high atom and step economical pathway. A proper modulation of the cinchona-derived squaramide catalysts efficiently provided access to all the possible stereoisomers with high yield, diastereoselectivity, and excellent enantioselectivity while displaying a broad substrate tolerance. Additionally, we validated the scalability of the reaction and demonstrated the synthesis of variable spiroaminal scaffolds, confirming the viability of our protocol.
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Affiliation(s)
- Prasenjit Gayen
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, 462066, India
| | - Suman Sar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, 462066, India
| | - Prasanta Ghorai
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, 462066, India
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4
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Midya A, Khalse LD, Ghorai P. Organocatalytic Enantioselective Intramolecular Michael Addition by In Situ Generated Aminoisobenzofulvenes: Construction of Spiro Quaternary Carbon Stereocenters. Chemistry 2023; 29:e202301563. [PMID: 37545475 DOI: 10.1002/chem.202301563] [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: 05/17/2023] [Revised: 07/28/2023] [Accepted: 08/05/2023] [Indexed: 08/08/2023]
Abstract
An unprecedented enantioselective organocatalytic spirocyclization strategy is presented by in situ generation of aminoisobezofulvenes. The reaction sequence involves a reductive Michael/aldol-condensation/Michael addition cascade by iminium-enamine catalysis. The key success of this spirocyclization was the formation of intermediatory nucleophilic aminoisobenzofuvenes accountable for intramolecular Michael addition. Benzospirononanes featuring an all carbon qauternary spirocenter were obtained using proline-derived amino-organocatalyst in moderate to good yields and excellent diastereo- and enantioselectivities (up to >20 : 1 dr, and 99 % ee). Post-methodological manipulation of benzospirononanes was also demonstrated.
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Affiliation(s)
- Abhisek Midya
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, 462066, India
| | - Laxman Devidas Khalse
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, 462066, India
| | - Prasanta Ghorai
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, 462066, India
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5
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Sar S, Ghorai P. An Intramolecular Umpolung Cascade Kukhtin-Ramirez Reaction/Michael Addition-Initiated Cyclization: Stereoselective Synthesis of Tetrasubstituted Cyclopropane Fused 1-Indanones. Org Lett 2023; 25:1946-1951. [PMID: 36920108 DOI: 10.1021/acs.orglett.3c00494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Herein, we disclose a fascinating highly stereoselective P(NMe2)3 mediated intramolecular deoxygenative umpolung cascade Michael addition-initiated cyclopropanation with a diverse substrate adaptability. This methodology creates a new horizon for expedient access to valuable 6,5,3-fused scaffolds having an all-carbon quaternary stereocenter via Kukhtin-Ramirez (K-R) adduct formation, with excellent diastereoselectivity and yields under metal-free ambient conditions. A few functional group transformations have also been performed successfully. Additionally, an asymmetric catalytic attempt using (R)-(+)-H8-BINOL has delivered good enantioselectivity.
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Affiliation(s)
- Suman Sar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal 462066, India
| | - Prasanta Ghorai
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal By-pass Road, Bhauri, Bhopal 462066, India
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6
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Han M, Liu C, Hu L. Enzyme-Catalyzed Dynamic Kinetic Resolution of 2-Formylbenzoic Acids for the Asymmetric Synthesis of Phthalidyl Esters and Related Prodrugs. J Org Chem 2023; 88:3897-3902. [PMID: 36821136 DOI: 10.1021/acs.joc.2c02531] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
An enzyme-catalyzed dynamic kinetic resolution strategy was applied for the asymmetric synthesis of phthalidyl esters in high yields (up to 95%) and enantiomeric purities (up to 99% ee) through a direct one-pot procedure. Preparation of phthalidyl ester prodrugs and a scale-up reaction demonstrated the potential of this method for practical applications.
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Affiliation(s)
- Maochun Han
- School of Pharmacy, Jiangsu University, Zhenjiang, 212013, China
| | - Changming Liu
- School of Pharmacy, Jiangsu University, Zhenjiang, 212013, China
| | - Lei Hu
- School of Pharmacy, Jiangsu University, Zhenjiang, 212013, China
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7
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Yan H, Shao X, Xu X, Li Z, Yang WL. Ir-Catalyzed Asymmetric Cascade Allylation/Spiroketalization Reaction for Stereoselective Synthesis of Oxazoline-Spiroketals. Org Lett 2023; 25:325-330. [PMID: 36607168 DOI: 10.1021/acs.orglett.2c03885] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
An asymmetric cascade allylation/spiroketalization reaction between 2-(1-hydroxyallyl)phenols and 5-methyleneoxazolines is accomplished by using a chiral Ir(I) catalyst derived from commercially available iridium precursor and the Carreira ligand. This protocol furnishes a class of structurally novel and unique oxazoline-spiroketals in up to 86% yield, >99% ee and >20:1 dr. Moreover, control experiments reveal that 4,4-disubstitution on 5-methyleneoxazolines is necessary to avoid the aromatization and for the spiroketalization to occur. On the basis of this, a plausible reaction mechanism is illustrated.
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Affiliation(s)
- Hui Yan
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China
| | - Xusheng Shao
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China
| | - Xiaoyong Xu
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China
| | - Zhong Li
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China
| | - Wu-Lin Yang
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China
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8
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Yang W, Shang X, Ni T, Yan H, Luo X, Zheng H, Li Z, Deng W. Diastereo‐ and Enantioselective Synthesis of Bisbenzannulated Spiroketals and Spiroaminals by Ir/Ag/Acid Ternary Catalysis. Angew Chem Int Ed Engl 2022; 61:e202210207. [DOI: 10.1002/anie.202210207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Wu‐Lin Yang
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy East China University of Science and Technology 130 Meilong Road Shanghai 200237 P. R. China
| | - Xin‐Yu Shang
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy East China University of Science and Technology 130 Meilong Road Shanghai 200237 P. R. China
| | - Tao Ni
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy East China University of Science and Technology 130 Meilong Road Shanghai 200237 P. R. China
| | - Hui Yan
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy East China University of Science and Technology 130 Meilong Road Shanghai 200237 P. R. China
| | - Xiaoyan Luo
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy East China University of Science and Technology 130 Meilong Road Shanghai 200237 P. R. China
| | - Hanliang Zheng
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Department of Chemistry Zhejiang Normal University Jinhua 321004 P. R. China
| | - Zhong Li
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy East China University of Science and Technology 130 Meilong Road Shanghai 200237 P. R. China
| | - Wei‐Ping Deng
- Shanghai Key Laboratory of Chemical Biology & School of Pharmacy East China University of Science and Technology 130 Meilong Road Shanghai 200237 P. R. China
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Department of Chemistry Zhejiang Normal University Jinhua 321004 P. R. China
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9
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Yang WL, Shang XY, Ni T, Yan H, Luo X, Zheng H, Li Z, Deng WP. Diastereo‐ and Enantioselective Synthesis of Bisbenzannulated Spiroketals and Spiroaminals by Ir/Ag/Acid Ternary Catalysis. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202210207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Wu-Lin Yang
- East China University of Science and Technology School of Pharmacy 130 Meilong Road 200237 Shanghai CHINA
| | - Xin-Yu Shang
- East China University of Science and Technology School of Pharmacy CHINA
| | - Tao Ni
- East China University of Science and Technology School of Pharmacy CHINA
| | - Hui Yan
- East China University of Science and Technology School of Pharmacy CHINA
| | - Xiaoyan Luo
- East China University of Science and Technology School of Pharmacy CHINA
| | - Hanliang Zheng
- Zhejiang Normal University Department of Chemistry CHINA
| | - Zhong Li
- East China University of Science and Technology School of Pharmacy CHINA
| | - Wei-Ping Deng
- East China University of Science and Technology School of Pharmacy CHINA
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10
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Hui Y, Man Z, Lin L, Teng H, Wulin Y. Advances in the Catalytic Asymmetric Synthesis of Chiral Spiroketals. CHINESE J ORG CHEM 2022. [DOI: 10.6023/cjoc202205001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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