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Li Z, Wang Y, Liu D, Ning L, Pu M, Lin L, Feng X. Chiral N, N'-Dioxide Ligands Tune Diastereoselectivity in Mg(II)-Catalyzed Asymmetric Ring-Opening Desymmetrization of Azetidiniums. Org Lett 2023; 25:7612-7616. [PMID: 37842957 DOI: 10.1021/acs.orglett.3c02728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
A diastereodivergent asymmetric desymmetrization of azetidinium salts with benzothiazoleamides as carbon nucleophiles through a chiral N,N'-dioxide/Mg(II) complex-promoted ring-opening reaction is realized by tuning ligands. Both syn- and anti-chiral δ-amino acid derivatives bearing benzothiazole structure were obtained in moderate to good yields and dr and ee values. DFT calculations indicated that the diastereodivergency stems from the different size of the chiral pocket formed by variable substructures of the ligands, leading to the opposite attack direction of the nucleophiles.
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Affiliation(s)
- Zhaojing Li
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Yan Wang
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Deyang Liu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Lichao Ning
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Maoping Pu
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Lili Lin
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Xiaoming Feng
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
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Reissig F, Mamat C. Strained Ammonium Precursors for Radiofluorinations. Chemistry 2022; 11:e202200039. [PMID: 35736542 PMCID: PMC9220932 DOI: 10.1002/open.202200039] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/24/2022] [Indexed: 12/11/2022]
Abstract
The increasing application of positron emission tomography (PET) in nuclear medicine has stimulated the extensive development of a multitude of novel and versatile techniques to introduce fluorine‐18, especially for the radiolabelling of biologically or pharmacologically active molecules. Taking into consideration that the introduction of fluorine‐18 (t1/2=109.8 min) mostly proceeds under harsh conditions, radiolabelling of such molecules represents a challenge and is of enormous interest. Ideally, it should proceed in a regioselective manner under mild physiological conditions, in an acceptable time span, with high yields and high specific activities. Special attention has been drawn to 2‐fluoroethyl and 3‐fluoropropyl groups, which are often the active sites of radiofluorinated compounds. Precursors containing an ammonium leaving group – such as a strained azetidinium or aziridinium moiety – can help to overcome these obstacles leading to a convenient and mild introduction of [18F]fluoride with high radiochemical yields.
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Affiliation(s)
- Falco Reissig
- Institut für Radiopharmazeutische Krebsforschung Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328, Dresden, Germany.,Fakultät Chemie und Lebensmittelchemie, Technische Universität Dresden, 01062, Dresden, Germany
| | - Constantin Mamat
- Institut für Radiopharmazeutische Krebsforschung Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328, Dresden, Germany.,Fakultät Chemie und Lebensmittelchemie, Technische Universität Dresden, 01062, Dresden, Germany
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