An Expeditious Benzannulation Reaction of Indol‐3‐yl‐but‐3‐yn‐2‐ols to Substituted 2‐Iodocarbazoles via Domino 5‐endo Spirocyclization/Selective Vinyl Shift and Aromatization. Issue 41 (28th October 2019)

• Record Type: Journal Article
• Authors: Yaragorla, Srinivasarao; Dada, Ravikrishna; Bag, Debojyoti
• Is Part Of: European journal of organic chemistry. Issue 41(2019)
• Page Start: 6983
• Page End: 6988
• Publication Date: 2019-10-28
• Subjects: 2‐Iodocarbazoles -- Iodocyclization -- Benzannulation -- Cross‐coupling -- Reaction mechanisms; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201901393
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : Regioselective benzannulation reaction of indol‐3‐yl‐but‐3‐yn‐2‐ols to functionaly embellished 2‐iodocarbazoles is described for the first time using iodine at room temperature in an open flask. This reaction proceeds through a cascade of 5‐ endo spirocyclization, ring‐rearrangement through a vinyl shift, and aromatization in a short time. This protocol offers direct access to uncovered 2‐iodocarbazoles, with a broad substrate scope and good to moderate yields. Further, we have demonstrated the synthetic potential of these compounds using cross‐coupling reactions. Abstract : A first approach to 2‐iodocarbazoles by benzannulation of indole‐tethered propargyl alcohols has been developed at room temperature in an open‐flask reaction using iodine. This benzannulation protocol involves a regioselective 5‐ endo ‐spirocyclization followed by a selective 1, 2‐alkenyl migration and aromatization cascade.