Asymmetric hydrogenation of acyclic enol esters

Tetrahedron Letters

Volumn 39, Issue 31, 1998, Pages 5505-5508

  Boaz, Neil W ^a  

^a EASTMAN CHEMICAL COMPANY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ACETYLENE DERIVATIVE; ALCOHOL; ESTER; VINYL DERIVATIVE;

ARTICLE; CATALYSIS; CATALYST; CHEMICAL REACTION; HYDROGENATION; STEREOCHEMISTRY;

EID: 0032581560     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(98)00730-8     Document Type: Article

References (13)

1. 1. (a) Koenig, K. E.; Bachman, G. L.; Vineyard, B. D. J. Org. Chem. 1980, 45, 2362.
2. (b) Selke, R.; Pracejus, H. J. Mol. Cat. 1986, 37, 213.
3. (c) Brown, J. M.; Murrer, B. A. J. Chem. Soc. Perkin Trans. 2 1982, 489.
4. (d) Fryzuk, M. D.; Bosnich, B. J. Am. Chem. Soc. 1978, 100, 5491.
5. (e) Ohta, T.; Miyake, T.; Seido, N.; Kumobayashi, H.; Tayaka, H. J. Org. Chem. 1995, 60, 357.
6. 2. Burk, M. J. J. Am. Chem. Soc. 1991, 113, 8518.
7. 3. Hrudlik, P. F.; Hrudlik, A. M. J. Org. Chem. 1973, 38, 4254.
8. 4. All of the asymmetric hydrogenations were performed under the same conditions. A typical procedure is exemplified for the preparation of 11a. Bis(cyclooctadienyl)rhodium tetrafluoroborate (10 mg; 0.025 mmol; 0.02 equiv)) and R,R-MeDuPHOS (R,R-3, 9 mg; 0.03 mmol; 0.024 equiv) were combined in a pressure tube under argon. The tube was evacuated and filled with argon five times and degassed THF (5 mL) was added to afford a yellow-orange solution. Enynyl acetate 9a (225 mg; 1.25 mmol) dissolved in 5 mL of degassed THF was then added. The reaction mixture was evacuated and filled with argon five times and then evacuated and filled with hydrogen three times. The reaction mixture was placed under 30 psi of hydrogen and stirred until hydrogen uptake had ceased (2 h). The vessel was vented and flushed with nitrogen, and the reaction mixture was concentrated to afford 0.26 g of the crude 11a. The enantiomeric excess of the product (98.5% ee) was determined without further purification.
9. 5. The absolute configuration was determined by correlation with R-2-nonanol: Mori, K.; Ogita, H. Leibigs Ann. Chem. 1994, 1065.
10. 6. The enantiomer ratio was determined by chiral capillary GC using a Cyclodex-B column (J&W Scientific).
11. 7. The absolute configuration was determined by correlation with R-4-phenyl-2-butanol: Burgess, K.; Jennings, L. D. J. Am. Chem Soc. 1991, 113, 6129.
12. 1H NMR analysis: Dale, J. A.; Dull, D. L.; Mosher, H. S. J. Org. Chem. 1969, 34, 2543.
13. 9. Karlsson, J. O.; Frejd, T. J. Org. Chem. 1983, 48, 1921.