Pd-catalyzed asymmetric allylation with a novel C 2 -symmetric bisphosphinite ligand: 3 R ,3′ R -bis(diphenylphosphinoxy)-6,6,6′,6′-tetramethyl-2 S ,2′ S -di-4 H -pyran
A novel C-2-symmetric chiral bisphosphinite ligand, 3R,3'R-bis(diphenylphosphinoxy)-6,6,6',6'-tetramethyl-2S,2'S-di-4H-pyran, was synthesized from D-mannitol and examined for palladium-catalyzed asymmetric allylic substitution. Under the optimized conditions, the allylation product can be obtained in up to 91.2% ee. (C) 2001 Elsevier Science Ltd. All rights reserved.
A new and efficient route to derivatives of (R)-4-hydroxycyclohex-2-enone
作者:Libing Yu、Ruzhou Zhang、Zhiqin Wang
DOI:10.1039/b107085a
日期:2001.11.15
A new and efficientroute has been developed to four derivatives of (R)-4-hydroxycyclohex-2-enone (7–10) from one intermediate, 6. These derivatives are useful chiral building blocks in the synthesis of natural products and in asymmetric reactions. The key step is a stereoselective intramolecular ene reaction with 4 Å MS as the Lewis acid and catalyst.