Asymmetric synthesis of 1,3-dialkyl-substituted carbon chains of any stereochemical configuration by an iterable process

Synlett

Volumn , Issue SPEC. ISS., 1997, Pages 457-459

  Myers, Andrew G ^a   Yang, Bryant H ^a   Chen, Hou ^a   Kopecky, David J ^a  

^a California Institute of Technology   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0003081972     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1997-6121     Document Type: Article

References (17)

1. Evans, D. A.; Dow, R. L.; Shih, T. L.; Takacs, J. M.; Zahler, R. J. Am. Chem. Soc. 1990, 112, 5290.
2. (a) Evans, D. A.; Takacs, J. M. Tetrahedron Lett. 1980, 21, 4233.
3. (b) White, J. D.; Johnson, A. T. J. Org. Chem. 1994, 59, 3347.
4. (a) Evans, D. A.; Ennis, M. D.; Mathre, D. J. J. Am. Chem. Soc. 1982, 104, 1737.
5. (b) Mathre, D. Ph.D. Thesis, California Institute of Technology, 1985.
6. Decicco, C. P.; Grover, P. J. Org. Chem. 1996, 61, 3534.
7. Enders, D.; Tiebes, J.; DeKimpe, N.; Keppens, M.; Stevens, C.; Smagghe, G.; Betz, O. J. Org. Chem. 1993, 55, 4881.
8. Nicolaou, K. C.; Yue, E. W.; La Greca, S.; Nadin, A.; Yang, Z.; Leresche, J. E.; Tsuri, T.; Naniwa, Y.; De Riccardis, F. Chem. Eur. J. 1995, 1, 467.
9. Myers, A. G.; Yang, B. H.; Chen, H.; Gleason, J. L. J. Am. Chem. Soc. 1994, 116, 9361.
10. In reactions where the amide was the limiting reagent, 2.1 equiv of LDA was used; when the alkyl iodide was limiting, 1.9 equiv was used.
11. Myers, A. G.; Yang, B. H. Kopecky, D. J. Tetrahedron Lett. 1996, 37, 3623.
12. Diastereomeric ratios of pseudoephedrine amides and primary alcohols were determined by chiral capillary GC analysis (Chirasil Val) of the corresponding acetate esters or trimethylsilyl ethers, with a detection limit of approximately 199:1.
13. (a) Garegg, P. J.; Samuelsson, B. J. Chem. Soc., Perkin Trans. I 1980, 2866.
14. (b) Lange, G. L.; Gottardo, C. Synth. Commun. 1990, 20, 1473.
15. Using 1.8 equiv of enolate (0.19 M), typical reaction times were 6-7 h at 23 °C for the formation of products 5 and 6, and 18 h at 23 °C for products 11-14. Lesser amounts of enolate could be employed with longer reaction times. For example, the reaction of iodide 4 with 1.3 equiv of the enolate derived from 1 (0.19 M) proceeded to completion within 18 h at 23 °C (90% yield, 66:1 selectivity).
16. A similar observation was reported in alkylations of prolinol-derived enolates (see ref. 2b).
17. Base-line resolution of mixtures of the 4 diastereomers 15-18 was achieved by chiral capillary GC analysis of the corresponding acetate esters.