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Substituted Cyclopentadienides of Magnesium from the Reaction of Dialkylmagnesium with Fulvenes
Author(s) -
Westerhausen Matthias,
Makropoulos Nikolaos,
Wieneke Birgit,
Karaghiosoff Konstantin,
Nöth Heinrich,
SchwenkKircher Holger,
Knizek Jörg,
Seifert Thomas
Publication year - 1998
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199807)1998:7<965::aid-ejic965>3.0.co;2-a
Subject(s) - chemistry , fulvene , cyclopentadienyl complex , magnesium , hydride , medicinal chemistry , cyclopropane , tetrahydrofuran , steric effects , deprotonation , reagent , stereochemistry , organic chemistry , hydrogen , ring (chemistry) , ion , catalysis , solvent
The reaction of n/sec ‐dibutyl magnesium with 6‐methyl‐6‐phenyl‐ and 6,6‐dicyclopropylfulvene gives the β‐hydride transfer products 1,1′‐bis(1‐phenylethyl)‐ and 1,1′‐bis‐(dicyclopropylmethyl)magnesocene, respectively. The latter crystallizes in the eclipsed conformation, whereas the first one shows an anti conformation in the solid state. Dimethyl‐magnesium deprotonates 6‐methyl‐6‐phenylfulvene with formation of 1,1′‐bis(1‐phenylethen‐1‐yl)magnesocene, which decomposes upon isolation. The deprotonation of 6,6‐dicyclopropylfulvene with MgMe 2 in thf solution yields [bis(tetrahydrofuran‐ O )][iro{cyclopropane‐1,2′(1′‐η 5 ‐cyclopentadienyl‐1′,3′,3′‐tricyclopropyl‐1′,2′,3′,3a′‐tetrahydropentalene)}‐3a′‐6′‐η 2 ‐enyl]magnesium. In the absence of β‐hydrogen atoms at the organometallic reagent as well as at the fulvene the addition reaction is the only possible reaction pathway. Thus, one Mg–C bond of MgMe 2 adds to tetramethylfulvene to give quantitatively dimeric methylmagnesium ethyltetramethylcyclopentadienide. The bridging methyl groups are sterically shielded against further attack of the fulvene.