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Umpolung Reactivity of Ynamides: An Unconventional [1,3]‐Sulfonyl and [1,5]‐Sulfinyl Migration Cascade
Author(s) -
Prabagar B.,
Mallick Rajendra K.,
Prasad Rangu,
Gandon Vincent,
Sahoo Akhila K.
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201813143
Subject(s) - umpolung , sulfonyl , cycloisomerization , chemistry , intramolecular force , alkyne , reactivity (psychology) , indole test , regioselectivity , propargyl , combinatorial chemistry , medicinal chemistry , catalysis , stereochemistry , organic chemistry , medicine , alkyl , alternative medicine , pathology , nucleophile
A regioselective sulfonyl/sulfinyl migration cycloisomerization cascade of alkyne‐tethered ynamides is developed in the presence of XPhosgold catalyst. This reaction is the first example of a general [1,3]‐sulfonyl migration from the nitrogen center to the β‐carbon atom of ynamides, followed by umpolung 5‐ endo ‐dig cyclization of the ynamide α‐carbon atom to the gold‐activated alkyne, and final deaurative [1,5]‐sulfinylation. This process allows the synthesis of peripherally decorated unconventional 4‐sulfinylated pyrroles with broad scope from N‐propargyl‐tethered ynamides. In contrast, N‐homopropargyl‐tethered ynamides undergo intramolecular tetradehydro Diels–Alder reaction to provide 2,3‐dihydro‐benzo[ f ]indole derivatives. Control experiments and density‐functional theory studies were used to study the reaction pathways.