Using stereoelectronic effects to explain selective reactions of 4-substituted five-membered ring oxocarbenium ions

Organic Letters

Volumn 6, Issue 12, 2004, Pages 2063-2066

  Smith, Deborah M ^a   Woerpel, K A ^a  

^a UNIVERSITY OF CALIFORNIA   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ACETAL; CARBENOID; ION;

ADDITION REACTION; ARTICLE; CHEMICAL REACTION; ELECTRON; MODEL; PREDICTION; STEREOCHEMISTRY;

EID: 3042828434     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol0492647     Document Type: Article

References (42)

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7. Numbering used in this paper considers the carbocationic carbon as C-1.
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9. Other five-membered ring cations are believed to undergo nucleophilic addition through similar low-energy staggered transition structures: (a) Bur, S. K.; Martin, S. F. Tetrahedron 2001, 57, 3221-3242. (b) Bach, T.; Brummerhop, H.; Harms, K. Chem. Eur. J. 2000, 6, 3838-3848.
10. Other five-membered ring cations are believed to undergo nucleophilic addition through similar low-energy staggered transition structures: (a) Bur, S. K.; Martin, S. F. Tetrahedron 2001, 57, 3221-3242. (b) Bach, T.; Brummerhop, H.; Harms, K. Chem. Eur. J. 2000, 6, 3838-3848.
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24. Acetals 7, 9, 15, 24, and 26 were prepared from the corresponding known lactones. Details of these experiments are provided as Supporting Information.
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31. 1H NMR spectroscopic analysis of unpurified reaction mixtures. The reported yields are based upon purified products (details of these experiments are provided as Supporting Information).
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36. 2 as the Lewis acid afforded a 54:46 ratio of cis: trans isomers for the allylation of 15.
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41. 2. With toluene as the solvent, selectivities were optimized to a 96:4 ratio of cis:trans isomers for the reaction of acetate 24.
42. Control experiments indicate that this reaction is irreversible at low (-78°C) reaction temperatures (details of these experiments are provided as Supporting Information).