Michael additions to metallocene analogues of chalcones

Abstract

Eleven analogues of chalcones were synthesized; the variously substituted ferrocenyl, ruthenocenyl or η5-cyclopentadienyltricarbonylmanganese are attached to the β-carbon of the chalcone double bond. Methyl malonate was added to eight selected chalcones. The effect of an aryl group on the chemical shift difference of diastereotopic -COOCH3 groups is discussed. The Vilsmeier-Haack formylation was employed to prepare 1'-chloro and 1'-bromoferrocenecarbaldehydes. The synthesis of 2-chloroferrocenecarbaldehyde from 2-chloroferrocenylmethyldimethylamine is also described.