A Route to Indoles via Modified Fischer Indole Intermediates from Sulfonanilides and Ketene Dithioacetal Monoxides. Issue 10 (1st September 2020)

• Record Type: Journal Article
• Authors: Kinoshita, Jun; Baralle, Alexandre; Yoshida, Akira; Yanagi, Tomoyuki; Nogi, Keisuke; Yorimitsu, Hideki
• Is Part Of: Asian journal of organic chemistry. Volume 9:Issue 10(2020)
• Page Start: 1655
• Page End: 1659
• Publication Date: 2020-09-01
• Subjects: indoles -- alkenyl sulfoxides -- anilines -- sigmatropic rearrangement -- interrupted Pummerer reaction; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; 547.005
• DOI: 10.1002/ajoc.202000397
• Languages: English
• ISSNs: 2193-5807

Abstract

Abstract: An S−N variant of the N−N‐based Fischer indole synthesis has been developed. Treatment of sulfonanilides and ketene dithioacetal monoxides with a powerful acid anhydride provides N ‐sulfonyl‐2‐methylsulfanylindoles. The initial interrupted Pummerer reaction would yield the key S−N‐tethered precursor in situ that then undergoes [3, 3] sigmatropic rearrangement, after which the endgame to the indole ring follows the Fischer manner. Abstract : The modern Pummerer chemistry has allowed the development of a new route to indoles from sulfonanilides and ketene dithioacetal monoxides. Upon activation of the sulfoxide with acid anhydride, an interrupted Pummerer reaction with sulfonanilide yielded an S−N variant of the N−N‐based intermediate in the Fischer indole synthesis. The S−N‐tethered intermediate follows a Fischer‐like pathway to the corresponding N ‐sufonyl‐2‐methylsulfanylindole of synthetic use.