Development of a convenient new synthetic route to [3]ferrocenophanones.
[3]Ferrocenophanone rac-8 was prepared by several non-Friedel-Crafts pathways starting from a Mannich-type coupling of 1,1'-diacetylferrocene followed by catalytic hydrogenation. Hydride abstraction from the resulting alpha-dimethylamino[3]ferrocenophane rac-14 with B(C6F5)3 followed by hydrolysis gave the ketone rac-8. Several variants of the Sommelet reaction, using ethylglyoxylate, formaldehyde or hexamethylenetetramine (urotropine) as the "oxidizing" reagent gave the alpha-[3]ferrocenophanone 8 in good to excellent yield. Some variants of these reactions were also used for the preparation of the pure enantiomer (R)-8. The electrochemical behaviour of 8 has been investigated and compared with related derivatives.
Organisch-Chemisches Institut der Universität Münster, Corrensstr. 40, D-48149, Münster, Germany.
Ludger
L
Tebben
Markus
M
Neumann
Gerald
G
Kehr
Roland
R
Fröhlich
Gerhard
G
Erker
Serena
S
Losi
Piero
P
Zanello