Addition of nitromethane to the chiral chromium tricarbonyl complex of o-tolualdehyde (1) gives, under conditions of kinetic control, the nitroalcohol 2 with ∼95% of asymmetric induction. Compound 2 then gives, in 3 steps, the corresponding aminoalcohol in about 40% yield. Use of nitroethane gives the nitroalcohol with a small diastereoselectivity at C(2)-C(3) (d.e. = 30 and 55%), but analogs of ephedrine and pseudoephedrine can be obtained optically pure by chromatography.
ASYMMETRIC-SYNTHESIS OF EPHEDRINE ANALOGS / A. SOLLADIE-CAVALLO, G. LAPITAJS, P. BUCHERT, A. KLEIN, S. COLONNA, A. MANFREDI. - In: JOURNAL OF ORGANOMETALLIC CHEMISTRY. - ISSN 0022-328X. - 330:3(1987 Aug), pp. 357-363.
ASYMMETRIC-SYNTHESIS OF EPHEDRINE ANALOGS
A. MANFREDIUltimo
1987
Abstract
Addition of nitromethane to the chiral chromium tricarbonyl complex of o-tolualdehyde (1) gives, under conditions of kinetic control, the nitroalcohol 2 with ∼95% of asymmetric induction. Compound 2 then gives, in 3 steps, the corresponding aminoalcohol in about 40% yield. Use of nitroethane gives the nitroalcohol with a small diastereoselectivity at C(2)-C(3) (d.e. = 30 and 55%), but analogs of ephedrine and pseudoephedrine can be obtained optically pure by chromatography.Pubblicazioni consigliate
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