Raju Chouhan, Nandini Ray, Nitish Nayan Gogoi, Sajal Kumar Das
{"title":"Dearomative Alkylation-Based Two-Step <i>cis</i>-Diastereoselective Synthesis of Indoline-2,3-Fused Chromans and Tetrahydropyrans.","authors":"Raju Chouhan, Nandini Ray, Nitish Nayan Gogoi, Sajal Kumar Das","doi":"10.1021/acs.joc.4c01726","DOIUrl":null,"url":null,"abstract":"<p><p>Herein, we describe a two-step, <i>cis</i>-diastereoselective synthesis of indoline-2,3-fused chromans from 3-substituted indoles. The method proceeds without intermediacy of <i>ortho</i>-quinone methides and leverages the dual function of TBS-protected 2-hydroxybenzyl iodides both as highly reactive alkylating agents in a <i>t</i>-BuONa/Et<sub>3</sub>B-promoted dearomative alkylation step and as a source of masked phenoxide nucleophiles in a subsequent TBAF-induced one-pot deprotection-cyclization step of the resulting indolenines. Importantly, this two-step protocol can also be extended to access indoline-2,3-fused tetrahydropyrans. These syntheses of indoline-2,3-fused chromans and tetrahydropyrans proceed with operational convenience, use easily accessible substrates and reagents, and feature broad substrate scope, high yields and complete diastereoselectivity. Furthermore, the synthesized products have the potential to undergo late-stage functionalization.</p>","PeriodicalId":57,"journal":{"name":"The Journal of Organic Chemistry","volume":null,"pages":null},"PeriodicalIF":3.3000,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Journal of Organic Chemistry","FirstCategoryId":"1","ListUrlMain":"https://doi.org/10.1021/acs.joc.4c01726","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/10/3 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"CHEMISTRY, ORGANIC","Score":null,"Total":0}
引用次数: 0
Abstract
Herein, we describe a two-step, cis-diastereoselective synthesis of indoline-2,3-fused chromans from 3-substituted indoles. The method proceeds without intermediacy of ortho-quinone methides and leverages the dual function of TBS-protected 2-hydroxybenzyl iodides both as highly reactive alkylating agents in a t-BuONa/Et3B-promoted dearomative alkylation step and as a source of masked phenoxide nucleophiles in a subsequent TBAF-induced one-pot deprotection-cyclization step of the resulting indolenines. Importantly, this two-step protocol can also be extended to access indoline-2,3-fused tetrahydropyrans. These syntheses of indoline-2,3-fused chromans and tetrahydropyrans proceed with operational convenience, use easily accessible substrates and reagents, and feature broad substrate scope, high yields and complete diastereoselectivity. Furthermore, the synthesized products have the potential to undergo late-stage functionalization.
期刊介绍:
The Journal of Organic Chemistry welcomes original contributions of fundamental research in all branches of the theory and practice of organic chemistry. In selecting manuscripts for publication, the editors place emphasis on the quality and novelty of the work, as well as the breadth of interest to the organic chemistry community.