Enantioselective Generation of 3-Amino-1-oxy-Substituted Carbanions by Sparteine-Induced Deprotonation: Asymmetric Synthesis of 3-Hydroxyalkylamines

Petra Sommerfeld; Dieter Hoppe

doi:10.1055/s-1992-21487

Synlett 1992; 1992(9): 764-766
DOI: 10.1055/s-1992-21487

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Enantioselective Generation of 3-Amino-1-oxy-Substituted Carbanions by Sparteine-Induced Deprotonation: Asymmetric Synthesis of 3-Hydroxyalkylamines

Petra Sommerfeld^* , Dieter Hoppe

^*Institut für Organische Chemie der Universität Kiel, Olshausenstr. 40-60, D-2300 Kiel, Germany

Abstract

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The O-3-dibenzylamino)propyl carbamate 3a is deprotonated by sec-butyllithium/(-)-sparteine with a high degree of selection between the enantiotopic methylene protons. After quenching the configurationally stable carbanionic intermediate 4a stereospecifically by electrophiles, γ-aminoalkanols 6 are obtained with ≥ 95% ee. The reaction of the dimethylamino derivative 3b under these conditions leads to essentially racemic products which presumably is caused by the competing internal complexation of the lithium cation.

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