Cycloaddition/ring opening reaction sequences of N-alkenyl aziridines: Influence of the aziridine nitrogen on stereoselectivity

Organic Letters

Volumn 10, Issue 1, 2008, Pages 57-60

  Siebert, Matthew R ^a   Yudin, Andrei K ^b   Tantillo, Dean J ^a  

^a UNIVERSITY OF CALIFORNIA   (United States)

^b UNIVERSITY OF TORONTO   (Canada)

Author keywords

[No Author keywords available]

Indexed keywords

AZIRIDINE DERIVATIVE; NITROGEN;

ARTICLE; CHEMICAL MODEL; CHEMICAL STRUCTURE; CHEMISTRY; CYCLIZATION; STEREOISOMERISM;

AZIRIDINES; CYCLIZATION; MODELS, CHEMICAL; MOLECULAR STRUCTURE; NITROGEN; STEREOISOMERISM;

EID: 38349154978     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol702623d     Document Type: Article

References (23)

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2. (a) Stork, G.; Terrell, R.; Szmuszkovicz, J. J. Am. Chem. Soc. 1954, 76, 2029-2030.
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7. For leading references on both thermal and photochemical (2 + 2) cycloaddition reactions, see: (a) Schuster, D. I.; Lem, G.; Kaprinidis, N. A. Chem. Rev. 1993, 93, 3-22.
8. (b) Nicolaou, K. C.; Lister, T.; Denton, R. M.; Gelin, C. F. Angew. Chem., Int. Ed. 2007, 46, 7501-7505.
9. 3a
10. For seminal discussions, see: (a) Kirmse, W.; Rondan, N. G.; Houk, K. N. J. Am. Chem. Soc. 1984, 106, 7989.
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14. (a) Woodward, R. B.; Hoffmann, R. The Conservation of Orbital Symmetry; Verlag Chemie: Weinheim, Germany, 1970.
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17. See Supporting Information for a movie of the reaction coordinate for a thermally allowed, concerted, suprafacial/antarafacial [2 + 2] reaction.
18. Structures 4 and 5 are conformers connected by several transition structures and intermediates that were elusive due to the small barriers. See Supporting Information for more details regarding the methods used in our attempts to locate said transition structures.
19. Structures 7 and 8 are conformers connected by two transition structures with energies of 0.6 and 1.5 kcal/mol relative to 7 (Figure 1). 8 sits at -2.1 kcal/mol relative to 7. See Supporting Information for details.
20. For a review, see: Seeman, J. I. Chem. Rev. 1983, 83, 83-134.
21. (a) In an attempt to measure the donating ability of the lone pair, proton affinities (PA) for various systems were calculated. No correlation was realized between PAs and the relative barrier height for the electrocyclic ring opening reaction, however. We will discuss this and other related topics in a future report.
22. (b) For another report of the unique directing ability of a N lone pair, see: Zhang, X.; Houk, K. N.; Leighton, J. L. Angew. Chem., Int. Ed. 2005, 44, 938-941.
23. It appears as though the barrier height for electrocyclic ring opening depends more upon σ donating effects of the alkyl groups than geometric effects of the aziridine. We will discuss this and other related topics in a future report.