The first enantioselective organocatalytic hydride reduction has been accomplished. The use of iminium catalysis has provided a new organocatalytic strategy for the enantioselective reduction of beta,beta-substituted alpha,beta-unsaturated aldehydes to generate beta-stereogenic aldehydes. The use of imidazolidinone 2 as the asymmetric catalyst has been found to mediate the transfer of hydrogen ...

The title mol-ecule, C(17)H(19)NO(5), was prepared by a Hantzsch dihydro-pyridine synthesis from 4-hy-droxy-benzaldehyde, methyl acetoacetate and NH(4)HCO(3). In the mol-ecular structure of the title compound, the dihydro-pyridine ring adopts a flattened boat conformation and the plane of the base of the boat forms a dihedral angle of 80.8 (2)° with the aromatic six-membered ring. The packing i...

hantzsch 1 ,4- dihy&opyridines; are rapidly oxidized to the corresponding pyridine derivatives using zinc chlorochromate nonahydrate [zn(c1cro ) .9h o] in dichloromethane at room temperature. in addition to aromatization, no loss of the 4- substituent is observed

A general process for the high-yielding synthesis of substituted chiral and achiral α-substituted acrylates was achieved through the sequential one-pot combination of a metal-free reductive coupling reaction followed by an Eschenmoser methylenation. The proline catalyzed reaction of Meldrum's acid, aldehydes and Hantzsch ester followed by methylenation was successful with Eschenmoser's salt in ...

This work concerns the synthesis of poly(pyrazolopyridine)s via a three-component Hantzsch reaction. The first part this study was intended to determine adequate experimental conditions for an analytically pure pyrazolopyridine heterocycle model compound in quantitative yield, which can be further used polymer synthesis. For purpose, effect different parameters (solvent, temperature, additive) ...

A three component reductive coupling reaction of a (hetero)aromatic amine, a (hetero)aromatic aldehyde and an electron deficient olefin catalysed by eosin Y under green LED light irradiation, for the direct generation of γ-amino acid derivatives, is described. This new umpolung synthesis of amines, which exploits the high nucleophilicity of a putative α-amino radical intermediate, generated via...

We have developed a direct amine/acid-catalyzed stereoselective hydrogenation of a variety of Wieland-Miescher (W-M) ketones, Hajos-Parrish (H-P) ketones and their analogs with organic hydrides (Hantzsch esters) as the hydrogen source. This astonishingly simple and biomimetic approach was used to construct highly functionalized chiral bicyclo[4.4.0]decane-1,6-diones in a diastereoselective fash...