Diastereoselective addition of organozinc and organomagnesium reagents to 2-(2'-pyrimidyl)ferrocenecarbaldehyde

ORGN 119

Albert Moyano, amoyano@ub.edu, Marta Omedes, and Ramon Rios, riosramon@yahoo.com. Departament de Química Orgànica, Universitat de Barcelona, Martí i Franquès, 1-11, Barcelona, 08028, Spain
Addition of diisopropylzinc, diethylzinc and isopropylmagnesium chloride to readily available 2-(2'-pyrimidyl)ferrocenecarbaldehyde takes place with high diastereo-selectivity to afford exclusively the alpha-ferrocenyl alcohol of (R*,pR*) configuration. On the other hand, the addition of ethyl- and methylmagnesium bromide leads to diastereomer mixtures in which the major isomer has the (S*,pR*) configuration. A unified mechanistic model accounting for this stereochemical outcome is proposed.