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Regiodivergent Control in the Gold(I) Catalyzed Synthesis of 7‐Pyrazolylindoles from 1‐Propargyl‐1 H ‐benzotriazoles and Ynamides through α‐Imino Gold(I) Carbene Complexes
Author(s) -
Allegue Darío,
González Jairo,
Fernández Sergio,
Santamaría Javier,
Ballesteros Alfredo
Publication year - 2019
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.201801484
Subject(s) - chemistry , regioselectivity , carbene , propargyl , nucleophile , substituent , catalysis , structural isomer , combinatorial chemistry , aryl , ligand (biochemistry) , medicinal chemistry , stereochemistry , organic chemistry , biochemistry , alkyl , receptor
A smooth, gold catalyzed, atom‐economical and regioselective synthesis of indoles is reported here. The reaction occurs from a nucleophilic attack of in situ synthesized triazapentalenes to gold activated ynamides and involves the participation of α‐imino gold carbene complexes. The use of sulfonyl ynamides drives the reaction to the formation of 2‐amidosubstituted indoles. However, the employment of 2‐oxazolidinolylynamides allows the formation of both isomers, such as, 2‐amido‐ and 3‐amidosubstituted indoles. In this case, the regioselection could be controlled by a correct choice of the catalyst ligand and the electron‐donating capability of the aryl substituent of the ynamide. A correct control in both parameters permits a totally regioselective synthesis of one or the other regioisomer. Isolation of key intermediates and X‐ray analysis allowed for a plausible explanation for this behavior.