A straightforward approach towards combined α-amino and α-hydroxy acids based on Passerini reactions

• Ameer F. Zahoor,
• Sarah Thies and
• Uli Kazmaier

Beilstein J. Org. Chem. 2011, 7, 1299–1303, doi:10.3762/bjoc.7.151

• chelated enolates and subsequent oxidation/Passerini reaction. This protocol works with both, aldehyde and ketone intermediates, as long as the ketones are activated by electron-withdrawing groups. In principle Ugi reactions are also possible, allowing the generation of diamino acid derivatives. Keywords

• : amino acids; chelated enolates; epoxides; Passerini reactions; Ugi reactions; Introduction Multicomponent reactions (MCR) are a very popular and powerful tool in modern organic synthesis [1][2][3][4]. Besides a wide range of heterocycle syntheses [5] and catalytic cross coupling reactions [6], the

• by chelated enolate Claisen rearrangement [22][23] or transition metal-catalyzed allylic alkylation of chelated enolates [24] and subsequent oxidative cleavage of the γ–δ-unsaturated amino acids obtained. Results and Discussion An alternative approach is based on regioselective ring opening of