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Cationic Iron Aminocarbene Complexes as Dienophiles in Diels‐Alder Reaction with Cyclopentadiene
Author(s) -
RückBraun Karola,
Köuhn Jörg
Publication year - 1996
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.19961290913
Subject(s) - cyclopentadiene , chemistry , cationic polymerization , dichloromethane , cycloaddition , steric effects , medicinal chemistry , diels–alder reaction , yield (engineering) , catalysis , stereochemistry , organic chemistry , materials science , metallurgy , solvent
The cationic iron (alkynyl)aminocarbene complexes [Cp(CO) 2 Fe(C(NHR)CCSiMe 3 ][PF 6 ], (R C 6 H 5 , p ‐CH 3 C 6 H 4 ) 1 derived from aromatic amines smoothly react with cyclopentadiene in dichloromethane to yield the cycloadducts 2 . No reaction was observed for complexes derived from sterically demanding aliphatic amines, like L ‐alanine tert ‐butyl ester. For comparison, the alkynyl‐substituted acyl iron compounds Cp(CO) 2 Fe(CO)CC̊ (R SiMe 3 , C 6 H 5 ) 3 were investigated, requiring TiCl 4 catalysis to undergo the cycloaddition reaction. The structures of the cycloadducts 4 were determined by X‐ray crystallography.