Synthesis and applications of a new class of C2 symmetric phosphorus donor ligand for asymmetric catalysis

Tetrahedron Asymmetry

Volumn 7, Issue 10, 1996, Pages 2809-2812

  Brenchley, Guy ^a   Fedouloff, Michael ^b   Merifield, Eric ^a   Wills, Martin ^a  

^a UNIVERSITY OF WARWICK   (United Kingdom)

^b GLAXOSMITHKLINE   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

BENZYL ALCOHOL DERIVATIVE;

ARTICLE; CHIRALITY; DRUG SYNTHESIS; PRIORITY JOURNAL; REACTION ANALYSIS; STEREOCHEMISTRY;

EID: 0030272367     PISSN: 09574166     EISSN: None     Source Type: Journal    
DOI: 10.1016/0957-4166(96)00368-0     Document Type: Article

References (15)

1. 1) (a) G. Brenchley, E. Merifield, M. Wills and M. Fedouloff, Tetrahedron Lett., 1994, 35, 2791.
2. (b) G. Brenchley, M. Fedouloff, M. F. Mahon, K. C. Molloy and M. Wills, Tetrahedron, 1995, 51, 10581.
3. 2) The significance of the array of four aromatic rings has been addressed in detail, for example; (a) R. Noyori, Chem. Soc. Rev., 1989, 18, 225.
4. (b) R. Noyori, Tetrahedron, 1994, 50, 4259.
5. (c) D. Seebach, E. Devaquet, A. Ernst, M. Hagakawa, F. N. M. Kuhnle, W. B. Schweiser and B. Weber, Angew. Chem. Int. Edn. Engl., 1995, 78, 1636 and references therein. See also reference 3.
6. 3) For excellent recent surveys see (a) R. Noyori, "Asymmetric Catalysis in Organic Synthesis", John Wiley and Sons Ltd, NY, 1994.
7. (b) I. Ojima, "Catalytic Asymmetric Synthesis", VCH Press, Berlin, 1993.
8. 4) The following are representative of the methods we attempted; 1,2-dibromoethane in THF, DMF or DMSO using sodium hydride (with and without added silver salts or 18-crown-6), butyllithium. potassium carbonate, P4 superbase; also with sodium hydride as base in THF: ethane-1,2-diol(bis)trifluorosulfonate, 1,2 diiodoethane, 1,3 dibromopropane, oxalyl chloride; ethane-1,2-diol with triphenylphosphine and DEAD.
9. 5) A sample of S-5 was generously provided by SmithKline Beecham, however for the synthesis of the antipodal diphosphine ligand it was necessary to prepare R-5 by the asymmetric reduction of o-bromoacetophenone using the method reported by Evans; D. A. Evans, S. G. Nelson, M. R. Gagne and A. R. Muci, J. Am. Chem. Soc., 1993, 115, 9800.
10. 6) A. S. Thompson, G. R. Humphrey, A. M. Demarco, D. J. Mathre and E. J. J. Grabowski, J. Org. Chem., 1993, 58, 5886.
11. 7) The methine protons in 2a and 2e appear as quartets at δ4.98 and 5.52 ppm respectively. Their cis-diastereoisomers have corresponding resonances at δ4.86 and 5.08 ppm (multiplet and sextet respectively). The same pattern is repeated in a derivative of 2a containing a 2-pyrollidylethyl group in the nitrogen atom, the relative configuration in which, like 2e, has been confirmed by X-ray crystallography. Compound (SpS)(SpS)-1 displayed a quartet at δ4.63 ppm for the methine resonance.
12. 8) For an excellent recent review see B. M. Trost, Chem. Rev. 1996, 96, 395.
13. 1 Hydrogenation product 9: chiral HPLC on Chiralcel OJ column; M. J. Burk, J. E. Feaster, W. A. Nugent and R. L. Harlow, J. Am. Chem.Soc., 1993, 115, 10125.
14. 10a - 10c: Chiral HPLC, Chiralcel OD column, 1.0-8% isopropanol (depending on sample) in hexane containing 0.1% diethylamine. 1-(1-Naphthyl)ethanol; chiral HPLC on Chiralcel OJ column using 8% isopropanol in hexane containing 0.1% diethylamine. Flow rates of 0.5-1ml/min give excellent separations although exact elution times and efficiency of separation depend on exact column dimensions and history. Further details will be given in a full paper. Absolute configurations confirmed for 10a to 10c and 1-(1-naphthyl)ethanol by optical rotation sign as given in ref. 5 and (a) M. B. Carter, B. Schiott, A. Gutierrez and S. L. Buchwald, J. Am. Chem. Soc., 1994, 116, 11667,
15. (b) G. B. Jones and S. B. Heaton, Tetrahedron: Asymmetry, 1993, 4 261.