New chiral phosphinamide catalysts for highly enantioselective reduction of ketones

Tetrahedron Letters

Volumn 37, Issue 16, 1996, Pages 2853-2856

  Gamble, Mark P ^a   Studley, John R ^a   Wills, Martin ^a  

^a UNIVERSITY OF WARWICK   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

ALKANOL; BENZYL ALCOHOL DERIVATIVE;

ARTICLE; CATALYSIS; CHIRALITY; DRUG SYNTHESIS; REACTION ANALYSIS; REDUCTION;

EID: 0029983325     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/0040-4039(96)00404-2     Document Type: Article

References (12)

1. B. Burns, J. R. Studley and M. Wills, Tetrahedron Lett., 1993, 34, 7105.
2. B. Burns, N. P. King, J. R. Studley, H. Tye and M. Wills, Tetrahedron: Asymmetry, 1994, 5, 801.
3. I. H. Williams, L. Linney and M. Wills, unpublished results.
4. The oxazaphospholidine ring opening reaction of related compounds has been reported to proceed with retention of configuration at phosphorus, for example: J. M. Brown, J. V. Carey and M. J. H. Russell, Tetrahedron, 1990, 46, 4877.
5. (a) H. M. I. Osborn, J. B. Sweeney and B. Howson, Synlett., 1994, 145.
6. (b) H. M. I. Osborn, A. A. Cantrill, J. B. Sweeney and B. Howson, Tetrahedron Lett., 1994, 35, 3159.
7. The reaction between prolinol and diphenylphosphinic chloride, in the presence of triethylamine and in dichloromethane solvent gave a large quantity of O-phosphinylated material. However the same reaction using diphenylprolinol gave mainly the N-phosphinylated product in 56% yield.
8. (a) J.-M. Brunel, O. Pardigon, B. Faure and G. Buono, J. Chem. Soc., Chem. Commun., 1992, 287.
9. (b) G. Buono, J.-M. Brunel, B. Faure and O. Pardigon, Phosphorus, Sulfur and Silicon, 1993, 93, 43.
10. J.-M. Brunel, M. Maffei and G. Buono, Tetrahedron: Asymmetry, 1993, 4, 2255.
11. In a typical procedure borane-dimethylsulfide complex (1.1 mmol) and catalyst (0.1 mmol) are dissolved in dry toluene (5 ml) and heated to 110°C. A solution of the ketone (1.0 mmol) in toluene (1 ml) is then added dropwise over 5 minutes. The reduction is essentially complete within a few minutes of the completion of the addition, however all reactions were heated for 90 minutes to ensure full conversion. The reaction is allowed to cool to room temperature, water (5 ml) is added and the product is extracted using dichloromethane (3 × 10 ml). After solvent removal the alcohol and the phosphinamide may be isolated by flash chromatography on silica gel. Enantiomeric excesses were measured by HPLC using a chiralcel OD column with 3-5% isopropanol in hexane, and 0.1% diethylamine as mobile phase.
12. O. Chiodi, F. Fotiadu, M. Sylvestre and G. Buono, Tetrahedron Lett., 1996, 37, 39.