Tetrahedron Letters

Modular pyridine-type P, N-ligands derived from monoterpenes: application in asymmetric Heck addition

AV Malkov, M Bella, IG Stará, P Kočovský

Index: Malkov, Andrei V.; Bella, Marco; Stara, Irena G.; Kocovsky, Pavel Tetrahedron Letters, 2001 , vol. 42, # 16 p. 3045 - 3048

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Citation Number: 62

Abstract

Novel (diphenylphosphinophenyl) pyridine ligands (+)-8,(+)-15,(−)-21, and (−)-26 were synthesized from (−)-β-pinene,(+)-3-carene,(+)-2-carene, and (−)-α-pinene, respectively, via Kröhnke annulation as the key step, and shown to effect≤ 88% ee in Heck addition (27→ 28). Ligands (+)-15 and (−)-21 are quasi-enantiomeric; ligands 8 and 26 can be prepared in both enantiomeric forms from (+)-and (−)-enantiomers of α-and β-pinene, respectively.