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Copper‐Catalyzed Selective Pyrrole Functionalization by Carbene Transfer Reaction
Author(s) -
Rodríguez Anabel M.,
Molina Francisco,
DíazRequejo M. Mar,
Pérez Pedro J.
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.201901629
Subject(s) - carbene , chemistry , diazo , pyrrole , medicinal chemistry , electrophile , alkyne , methylene , aryl , alkyl , catalysis , ring (chemistry) , alkylation , organic chemistry
1 H ‐Pyrroles can be directly functionalized by means of the incorporation of carbene groups from diazo compounds, in a process catalyzed by Tp x Cu complexes (Tp x =hydrotrispyrazolylborate ligand). The reactions take place with a complete selectivity toward the formal insertion of the carbene into the C α −H bond, leading to alkylated pyrroles, with no modification of the C β −H, N−H or C=C bonds of the pyrrole unit. Alkyl substituents at C‐ring as well as alkyl, aryl, allyl or alkyne substitution at N atom are tolerated, the strategy affording 20 new pyrrole derivatives. The observance of partial deuteration at the methylene group when the reaction is carried out with added D 2 O serves to discard the direct insertion of the carbene group into the C sp 2 −H bond, the alternative electrophilic attack to the pyrrole ring being feasible.