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Free-Radical Telomerization of Chiral Acrylamides: Control of Stereochemistry in Additions and Halogen-Atom Transfer

Publication ,  Journal Article
Porter, NA; Breyer, R; Swann, E; Nally, J; Pradhan, J; Allen, T; McPhail, AT
Published in: Journal of the American Chemical Society
August 1, 1991

The free-radical reactions of carbon radicals substituted α to a chiral pyrrolidine amide have been studied. The pyrrolidine used was 2,5-dimethylpyrrolidine, available as either the R,R or S,S enantiomer from d- or l-alanine, and the radicals were generated (1) by tin radical abstraction of the halogen from the 2-iodobutyramide of the pyrrolidine, (2) by decomposition of a pyrrolidine amide substituted Barton ester 4, and (3) by radical addition to the acrylamide of the pyrrolidine 3. Addition of chiral α amide radicals to alkenes occurs with a selectivity of ∼15:1 at room temperature, while bromine-and iodine-atom transfer to these radicals occurs with a selectivity of 10:1 at room temperature. Telomerization of the acrylamide 3 is achieved by photolysis of BrCCl3 in the presence of acrylamide. Telomers are readily formed and the lower telomers, n = 1 to 5, were isolated and characterized. Halogens were removed from the telomers by reduction with tributyltin hydride and in this way, the major diastereomers of the n = 2 and n = 3 telomers were converted to known compounds. Chain-transfer constants for the BrCCl3 telomerization were determined and they range from 0.3 to 0.5 for Cn = C2 to C5. An analysis of the chiral amide auxiliary is presented that may prove useful in the consideration of other auxiliary groups. © 1991, American Chemical Society. All rights reserved.

Duke Scholars

Published In

Journal of the American Chemical Society

DOI

EISSN

1520-5126

ISSN

0002-7863

Publication Date

August 1, 1991

Volume

113

Issue

18

Start / End Page

7002 / 7010

Related Subject Headings

  • General Chemistry
  • 40 Engineering
  • 34 Chemical sciences
  • 03 Chemical Sciences
 

Citation

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MLA
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Porter, N. A., Breyer, R., Swann, E., Nally, J., Pradhan, J., Allen, T., & McPhail, A. T. (1991). Free-Radical Telomerization of Chiral Acrylamides: Control of Stereochemistry in Additions and Halogen-Atom Transfer. Journal of the American Chemical Society, 113(18), 7002–7010. https://doi.org/10.1021/ja00018a044
Porter, N. A., R. Breyer, E. Swann, J. Nally, J. Pradhan, T. Allen, and A. T. McPhail. “Free-Radical Telomerization of Chiral Acrylamides: Control of Stereochemistry in Additions and Halogen-Atom Transfer.” Journal of the American Chemical Society 113, no. 18 (August 1, 1991): 7002–10. https://doi.org/10.1021/ja00018a044.
Porter NA, Breyer R, Swann E, Nally J, Pradhan J, Allen T, et al. Free-Radical Telomerization of Chiral Acrylamides: Control of Stereochemistry in Additions and Halogen-Atom Transfer. Journal of the American Chemical Society. 1991 Aug 1;113(18):7002–10.
Porter, N. A., et al. “Free-Radical Telomerization of Chiral Acrylamides: Control of Stereochemistry in Additions and Halogen-Atom Transfer.” Journal of the American Chemical Society, vol. 113, no. 18, Aug. 1991, pp. 7002–10. Scopus, doi:10.1021/ja00018a044.
Porter NA, Breyer R, Swann E, Nally J, Pradhan J, Allen T, McPhail AT. Free-Radical Telomerization of Chiral Acrylamides: Control of Stereochemistry in Additions and Halogen-Atom Transfer. Journal of the American Chemical Society. 1991 Aug 1;113(18):7002–7010.
Journal cover image

Published In

Journal of the American Chemical Society

DOI

EISSN

1520-5126

ISSN

0002-7863

Publication Date

August 1, 1991

Volume

113

Issue

18

Start / End Page

7002 / 7010

Related Subject Headings

  • General Chemistry
  • 40 Engineering
  • 34 Chemical sciences
  • 03 Chemical Sciences