Tetrahedron letters

Enantioselective hantzsch dihydropyridine synthesis via metalated chiral alkyl acetoacetate hydrazones1

D Enders, S Müller, AS Demir

Index: Enders, Dieter; Mueller, Stephan; Demir, Ayhan S. Tetrahedron Letters, 1988 , vol. 29, # 49 p. 6437 - 6440

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Citation Number: 73

Abstract

An efficient, overall enantioselective variant of the Hantzsch synthesis of 4-aryl-1,4-dihydropyridines (ee = 84 - 98%), important biologically active compounds (eg as calcium channel blockers), is described. Key step of the new procedure is the asymmetric Michael addition of metalated chiral alkyl acetoacetate hydrazones ( )- to the Knoevenagel acceptors . An accurate method to determine the enantiomeric excess of chiral dihydropyridines is also reported.