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Synthesis of 3‐Substituted Chalcogenophene‐Fused Indoles from 2‐Alkynylindoles
Author(s) -
Leonel Guilherme,
Back Davi F.,
Zeni Gilson
Publication year - 2020
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201901213
Subject(s) - chemistry , electrophile , diselenide , combinatorial chemistry , indole test , thiophene , intramolecular force , selenium , diphenyl diselenide , bicyclic molecule , organic chemistry , medicinal chemistry , catalysis
The intramolecular electrophilic cyclization of 3‐organoselanyl‐2‐alkynylindoles providing the synthesis of 3‐iodo‐selenophene‐fused indoles is reported herein. The strategy was extended to the preparation of 3‐iodo‐thiophene‐fused indoles in a one‐pot iodine‐promoted thiolation of 2‐alkynylindoles, followed by an electrophilic cyclization sequence. Besides, the synthesis of 3‐butylselanyl‐selenophene‐fused indoles from 3‐butylselanyl‐2‐alkynylindoles was also developed using iron(III) chloride and dibutyl diselenide to promote the cyclization and functionalization of the heterocycle. The identification of the alkyl halide intermediate afforded evidence to the proposed mechanism, which indicated that the reactions proceed through the formation of an iodonium ion, followed by a selenium 5‐ endo ‐dig cyclization, to afford the indole derivatives. The 3‐iodo‐selenonophene‐fused indoles prepared were applied as substrates in copper‐catalyzed cross‐coupling reactions with thiols to give the Ullmann type products in good yields.