The chiral formylferrocenes 2−5 have been readily prepared in good yields by ortho-lithiation of the TMS-blocked orunblocked aminoferrocenes and subsequent reaction with DMF. The stereochemistry of the reaction of 2 with organometallic reagents has been examined. Reactions of 2 with Grignard and organolithium reagents gave the corresponding amino alcohol 6 in good yields with moderate to high diastereomeric excesses (up to 99%). When a dialkylzinc was used as the nucleophile, a single diastereomer was obtained almost exclusively. This reaction may be rationalized in terms of an autocatalytic mechanism; the zinc alkoxide 7 generated in situ functions as an activator of dialkylzinc, which then adds to the formyl group. We have examined the asymmetric diethylzinc addition to benzaldehyde using formylferrocenes 2−5 or ferrocenyl amino alcohols 6a, 13 as catalysts, especially with regard to the relationship between catalytic activ-
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