Enantioselective addition of diethylzinc to ferrocene carbaldehyde - reaction outcome by using natural compound based catalysts

The efficiency of the alkaloids quinine, cinchonine, cinchonidine and ephedrine, the aminoalcohols prolinol, and alaninol, as well as the aminoacids proline, and phenylalanine as catalysts for the enantioselective addition of diethylzinc to ferrocene carbaldehyde and benzaldehyde has been studied. The addition reactions proceeded with acceptable yields and low to moderate enantioselectivities. The side products ferrocenyl methanol and 1 -ferrocenyl-1-propanone, observed during the additions to ferrocene carbaldehyde were isolated and characterized.