Unsymmetrically disubstituted ferrocenes. Part IX. The condensation of 1-dimethylaminomethyl-2-lithioferrocene with acetaldehyde, acetylferrocene, and pyridine; (2-pyridyl)ferrocene derivatives

Abstract

The reaction of 1-dimethylaminomethyl-2-lithioferrocene with acetaldehyde gave the corresponding alcohol, which was isolated as a mixture of two diastereoisomers. The lithio-amine was also condensed with acetylferrocene to give the corresponding alcohol, which was converted into 1-dimethylaminomethyl-2-(1-ferrocenylvinyl)ferrocene. Acetylferrocene underwent an aldol-type condensation in the presence of n-butyl-lithium to give 1,3-diferrocenylbut-2-en-1-one. The condensation of lithiated 2-pyridylferrocene with tri-n-butyl borate gave 2-(2-pyridyl)ferroceneboronic acid. This amino-acid was converted into the corresponding 2-chloro-, 2-bromo-, and 2-iodo(2-pyridyl)ferrocenes. The lithio-amine was also condensed with benzonitrile, paraformaldehyde, and dimethylformamide. With 1-dimethylaminomethyl-2-lithioferrocene, pyridine afforded 1-dimethylaminomethyl-2-(2-pyridyl)ferrocene; the mono-methiodide of this diamine underwent nucleophilic displacement and oxidation.