New heterogeneous catalyst for enantioselective borane reduction of ketones: Phosphinamide anchored to nickel boride

Tetrahedron Asymmetry

Volumn 11, Issue 15, 2000, Pages 3049-3052

  Cividino, Pascale ^a   Masson, Jacqueline ^a   Molvinger, Karine ^a   Court, Jean ^a  

^a UNIVERSITÉ JOSEPH FOURIER   (France)

Author keywords

[No Author keywords available]

Indexed keywords

ACETOPHENONE; AMIDE; BORANE DERIVATIVE; KETONE; KETONE DERIVATIVE; NICKEL COMPLEX;

CATALYST; ENANTIOMER; PRIORITY JOURNAL; SHORT SURVEY; STEREOSPECIFICITY;

EID: 0034637180     PISSN: 09574166     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0957-4166(00)00278-0     Document Type: Article

References (17)

1. Molvinger, K.; Lopez, M.; Court, J. J. Mol. Catal. 1999, 150, 267.
2. Molvinger, K.; Lopez, M.; Court, J. Tetrahedron Lett. 1999, 40, 8375.
3. Corey, J. E.; Helal, C. J. Angew. Chem., Int. Ed. Engl. 1998, 37, 1986.
4. Buono, G.; Chiodi, O.; Wills, M. Synlett 1999, 4, 377.
5. Burns, B.; King, N. P.; Tye, H.; Studley, J. R.; Gamble, M.; Wills, M. J. Chem. Soc., Perkin Trans. 1 1998, 377.
6. Burns, B.; King, N. P.; Studley, J. R.; Tye, H.; Wills, M. Tetrahedron: Asymmetry 1994, 5, 801.
7. Burns, B.; Studley, J. R.; Wills, M. Tetrahedron Lett. 1993, 34, 7105.
8. 5
9. 2 (10 mmol) in THF (80 ml). After 16 h at reflux, the THF was decanted and removed. The catalyst was then washed with 80 ml of THF before use. No trace of the phosphinamide was detected by g.l.c. analysis of the solvent.
10. Borane-THF (0.6 equivalent) was added to a stirred suspension of phosphinamide bound to nickel boride in 40 ml of THF at room temperature under nitrogen. After 1 min, 1 equivalent of acetophenone was added. The mixture was stirred at room temperature until the reaction was complete (g.l.c. analysis). The solids were allowed to settle and the liquid phase was removed through a transfer tube by means of a pressure differential, the catalyst being left in the flask. Before reuse, the solids were washed with 80 ml of solvent. The liquid phase was diluted with 2 M HCl and extracted with ethyl acetate, which was then washed with saturated aqueous NaCl, dried, and evaporated. The enantiomeric purity of the product was determined by capillary GC with a chiral column (hydrodex β cyclodextrin, 25 m-0.25 mm Macherey-Nagel).
11. Salunke, A. M.; Burkhardt, E. R. Tetrahedron Lett. 1997, 38, 1523.
12. Salunke, A. P.; Burkhardt, E. R. Tetrahedron Lett. 1997, 38, 1519
13. Cai, D.; Tschaen, D.; Shi, Y. J.; Verhoeven, T. R.; Reamer, A. R.; Douglas, A. W. Tetrahedron Lett. 1993, 34, 3243.
14. Gamble, M. P.; Studley, J. R.; Wills, M. Tetrahedron Lett. 1996, 37, 2853.
15. Gamble, M. P.; Studley, J. R.; Wills, M. Tetrahedron: Asymmetry 1996, 7, 3071.
16. Gamble, M. P.; Smith, A. R. C.; Wills, M. J. Org. Chem. 1998, 63, 6068.
17. 2 (10 mmol in 80 ml DCM). After 16 h at room temperature, 0.45 mmol of hydrogen was obtained. The solid was washed with 80 ml DCM before use in the experimental conditions described for the phosphinamide.With the borane-N,N-diethylaniline as reducing agent, the catalyst gives (S)-1-phenylethanol with ee = 6%. The ee is low, since both oxygen atoms have similar coordinating capability to the borane. However, the catalyst can be recycled two times with no loss of performance, thus the diol is strongly bound to the nickel boride suggesting the formation of a dioxaborolidine.