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Hsu CM, Lin HB, Hou XZ, Tapales RVPP, Shih CK, Miñoza S, Tsai YS, Tsai ZN, Chan CL, Liao HH. Azetidines with All-Carbon Quaternary Centers: Merging Relay Catalysis with Strain Release Functionalization. J Am Chem Soc 2023; 145:19049-19059. [PMID: 37589099 DOI: 10.1021/jacs.3c06710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Given the importance and beneficial characteristics of decorated azetidines in medicinal chemistry, efficient strategies for their synthesis are highly sought after. Herein, we report a facile synthesis of the elusive all-carbon quaternary-center-bearing azetidines. By adopting a well-orchestrated polar-radical relay strategy, ring strain release of bench-stable benzoylated 1-azabicyclo[1.1.0]butane (ABB) can be harnessed for nickel-catalyzed Suzuki Csp2-Csp3 cross-coupling with commercially available boronic acids in broad scope (>50 examples), excellent functional group tolerance, and gram-scale utility. Preliminary mechanistic studies provided insights into the underlying mechanism, wherein the ring opening of ABB with a catalytic quantity of bromide accounts for the conversion of ABB into a redox-active azetidine, which subsequently engages in the cross-coupling reaction through a radical pathway. The synergistic bromide and nickel catalysis could intriguingly be derived from a single nickel source (NiBr2). Application of the method to modify natural products, biologically relevant molecules, and pharmaceuticals has been successfully achieved as well as the synthesis of melanocortin-1 receptor (MC-1R) agonist and vesicular acetylcholine transporter (VAChT) inhibitor analogues through bioisosteric replacements of piperidine with azetidine moieties, highlighting the potential of the method in drug optimization studies. Aside from the synthesis of azetidines, we demonstrate the ancillary utility of our nickel catalytic system toward the restricted Suzuki cross-coupling of tertiary alkyl bromides with aryl boronic acids to construct all-carbon quaternary centers.
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Affiliation(s)
- Che-Ming Hsu
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Heng-Bo Lin
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Xin-Zhi Hou
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | | | - Chen-Kuei Shih
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Shinje Miñoza
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Yu-Syuan Tsai
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Zong-Nan Tsai
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Cheng-Lin Chan
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Hsuan-Hung Liao
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
- Green Hydrogen Research Center, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
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Li B, Xu FL, Xia M, Li XM, Zhao H, Hou XZ. [External laryngoceles with fluid: a case report]. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2023; 58:797-799. [PMID: 37599243 DOI: 10.3760/cma.j.cn115330-20230509-00215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Affiliation(s)
- B Li
- Shandong Provincial Hospital Affiliated to Shandong First Medical University, Otorhinolaryngology Head and Neck Surgery,Jinan 250021, China
| | - F L Xu
- Shandong Provincial Hospital Affiliated to Shandong First Medical University, Otorhinolaryngology Head and Neck Surgery,Jinan 250021, China
| | - M Xia
- Shandong Provincial Hospital Affiliated to Shandong First Medical University, Otorhinolaryngology Head and Neck Surgery,Jinan 250021, China
| | - X M Li
- Shandong Provincial Hospital Affiliated to Shandong First Medical University, Otorhinolaryngology Head and Neck Surgery,Jinan 250021, China
| | - H Zhao
- Shandong Provincial Hospital Affiliated to Shandong First Medical University, Otorhinolaryngology Head and Neck Surgery,Jinan 250021, China
| | - X Z Hou
- Shandong Provincial Hospital Affiliated to Shandong First Medical University, Otorhinolaryngology Head and Neck Surgery,Jinan 250021, China
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