{"title":"Metal-Free Access to (Spirocyclic)Tetrahydro-β-carbolines in Water Using an Ion-Pair as a Superacidic Precatalyst","authors":"Zhenguo Zhang, Xiaoxiao Liu, Liang Ji, Ting Zhang, Zhenhua Jia*, Teck-Peng Loh*","doi":"10.1021/acscatal.1c05546","DOIUrl":null,"url":null,"abstract":"<p >The unprecedented triarylcarbonium ion-pair-catalyzed Pictet–Spengler reaction of tryptamines with aromatic aldehydes and cyclic ketones in water was disclosed. Under metal-free conditions, diverse tetrahydro-β-carbolines and <i>spirocyclic</i> tetrahydro-β-carbolines were obtained in good yields with excellent functional group tolerance, including late-stage modification of natural products and small molecular drugs. The practicability of this protocol is also characterized in the gram-scale synthesis of Komavine and several other functional compounds. Preliminary mechanistic studies indicated that in aqueous media the <i>in situ</i>-generated superacidic species from the carbonium ion pair with water was crucial to promote the Pictet–Spengler reaction.</p>","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"12 3","pages":"2052–2057"},"PeriodicalIF":11.3000,"publicationDate":"2022-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"4","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acscatal.1c05546","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 4
Abstract
The unprecedented triarylcarbonium ion-pair-catalyzed Pictet–Spengler reaction of tryptamines with aromatic aldehydes and cyclic ketones in water was disclosed. Under metal-free conditions, diverse tetrahydro-β-carbolines and spirocyclic tetrahydro-β-carbolines were obtained in good yields with excellent functional group tolerance, including late-stage modification of natural products and small molecular drugs. The practicability of this protocol is also characterized in the gram-scale synthesis of Komavine and several other functional compounds. Preliminary mechanistic studies indicated that in aqueous media the in situ-generated superacidic species from the carbonium ion pair with water was crucial to promote the Pictet–Spengler reaction.
期刊介绍:
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.