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Pyrrole and Oligopyrrole Synthesis by 1,3‐Dipolar Cycloaddition of Azomethine Ylides with Sulfonyl Dipolarophiles
Author(s) -
RoblesMachín Rocío,
LópezPérez Ana,
GonzálezEsguevillas María,
Adrio Javier,
Carretero Juan Carlos
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201000742
Subject(s) - cycloaddition , sulfonyl , chemistry , 1,3 dipolar cycloaddition , azomethine ylide , pyrrole , catalysis , combinatorial chemistry , organic chemistry , alkyl
A procedure for the synthesis of functionalized, substituted pyrroles by 1,3‐dipolar cycloaddition of azomethine ylides has been developed. This protocol is based on the metal‐catalyzed cycloaddition of α‐iminoesters with sulfonyl dipolarophiles, followed by the base‐promoted elimination of the sulfonyl groups. A wide variety of 2,5‐disubstituted and 2,3,5‐ and 2,4,5‐trisubstituted pyrroles have been prepared in satisfactory yields from 1,2‐bis(sulfonyl ethylene), β‐sulfonylenones, and β‐sulfonylacrylates. This method can be applied in an iterative and straightforward manner to the construction of oligopyrroles, from bipyrroles to pentapyrroles. Iterative [ n +1] and [ n +2] approaches have been devised, the latter involves double 1,3‐dipolar cycloaddition from pyrrolyl‐based bis(iminoesters).