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[reaction: see text] N-Acyl aldohydrazones I (R = CO(2)Et, alkyl, aryl, and furyl) efficiently trap the 1,3-dioxolanyl radical intermolecularly without external activation at temperatures as low as -78 degrees C. For alkyl aldohydrazones, good diastereoselectivities are obtained in the presence of InCl(3) at low temperature. Elaboration of the adducts (II) allows for the asymmetric synthesis of alpha-amino acid derivatives.

New copper(II) complexes of asymmetrical tetradentate Schiff bases containing pyrazine have been prepared and thoroughly characterised by elemental analysis, IR and electronic spectroscopy, mass spectrometry and magnetic measurements. Two alternative methods were used in the isolation of the complexes: template synthesis in the preparation of Cu(SalDpyz)ClO 4 (HSalDPyz = derived from the condensation of salicylaldehyde, acetylpyrazine and 1,2ethylendiamine, 2-methyl-1,2-propylendiamine, 1,2-phenylendiamine) and direct interaction between copper perchlorate and the corresponding Schiff base, as in the isolation of Cu (AEPyz)(ClO 4 ) (HAEPyz = (Z)-4-[2-{[2-{[(E)-1-(pyrazinyl)ethylidene]amino} ethyl)amino]-3-penten-2-one)]. [Cu(SalEn)(py)(OClO 3 )][Cu(SalEn)(py)]ClO 4 (1) (SalEn = 4-(2-hydroxyphenyl)-3-aza-3-buten-1-amino, py = pyridine), metal precursor in the preparation of Cu(SalEnpyz)(ClO 4 ) (HSalEnpyz = 2-{E(2-{[(E)-1-(2-pyrazinyl)ethylidene]amino}ethyl)imino]methyl}phenol), was crystallographically characterised. The crystal structure of [Cu(AEpyz)]ClO 4 (2) is also reported.

Aminocarboxylic acids (hydrazinocarboxylic acids) and estersAminocarboxylic acids (hydrazinocarboxylic acids) and esters P 0270Diastereoselective Intermolecular Addition of the 1,3-Dioxolanyl Radical to N-Acyl Aldohydrazones. Asymmetric Synthesis of α-Amino Acid Derivatives. -N-Acyl aldohydrazones efficiently trap the 1,3-dioxolanyl radical without external activation at temperatures as low as -78°C. The process can be efficiently carried out as a one-pot procedure starting from aldehydes and leads to (IV) in good yields and high stereoselectivities (for the alkyl derivatives). The method is used as key step for the asymmetric synthesis of α-amino acid (V). -(FERNANDEZ, M.; ALONSO*, R.; Org. Lett. 5 (2003) 14, 2461-2464; Dep. Quim. Org., Fac. Farm., Univ. Santiago de Compostela, E-15782 Santiago de Compostela, Spain; Eng.) -Steudel 48-066