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Michael Addition of Imines to Alkynylcarbene Complexes with Subsequent Intramolecular Cyclization ‐ An Efficient Three‐Step Synthesis of 2 H ‐Pyrroles
Author(s) -
Funke Frank,
Duetsch Michael,
Stein Frank,
Noltemeyer Matthias,
Meijere Armin De
Publication year - 1994
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19941270520
Subject(s) - chemistry , carbene , chromium , intramolecular force , tetrahydrofuran , medicinal chemistry , michael reaction , aldimine , intramolecular reaction , stereochemistry , polymer chemistry , organic chemistry , catalysis , solvent
Imines 7 , 11–13 were added to (1‐alkynylcarbene)chromium complexes 6a–d to form {[2‐(methyleneamino)ethenyl]‐carbene}chromium complexes 8a–d , 14a–d , 15a–d , 16a–d in good to very good yields (63–98%) except for two cases (41–59%). The carbene ligands of the latter compounds cyclize to 2 H ‐pyrroles 9a–d , 17a–d , 18a–d , 19a–d upon heating in tetrahydrofuran solution to 50–55°C.