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Volumn 73, Issue 1, 2008, Pages 102-110

Density functional theory guided design of exo-selective dehydroalanine dienophiles for application toward the synthesis of palau'amine

Author keywords

[No Author keywords available]

Indexed keywords

DEHYDROALANINE DIENOPHILES; DFT COMPUTATIONS; DIELS-ALDER CYCLOADDITIONS; PALAU'AMINE;

EID: 37549031235     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo701866g     Document Type: Article
Times cited : (50)

References (68)
  • 4
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    • For, konbu'acidin A, a close relative of palau'amine, see
    • (d) For, konbu'acidin A, a close relative of palau'amine, see: Kobayashi, J.; Suzuki, M.; Tsuda, M. Tetrahedron 1997, 53, 15681.
    • (1997) Tetrahedron , vol.53 , pp. 15681
    • Kobayashi, J.1    Suzuki, M.2    Tsuda, M.3
  • 5
    • 24644462320 scopus 로고    scopus 로고
    • For reviews of synthetic studies toward palau'amine and its relatives, see: a
    • For reviews of synthetic studies toward palau'amine and its relatives, see: (a) Jacquot, D. E. N.; Lindel, T. Curr. Org. Chem. 2005, 9, 1551.
    • (2005) Curr. Org. Chem , vol.9 , pp. 1551
    • Jacquot, D.E.N.1    Lindel, T.2
  • 8
    • 33746288746 scopus 로고    scopus 로고
    • For recent synthetic studies toward palau'amine and its relatives, see: a
    • For recent synthetic studies toward palau'amine and its relatives, see: (a) Tan, X.; Chen, C. Angew. Chem., Int. Ed. 2006, 45, 4345.
    • (2006) Angew. Chem., Int. Ed , vol.45 , pp. 4345
    • Tan, X.1    Chen, C.2
  • 21
    • 0034644391 scopus 로고    scopus 로고
    • Carreira has developed a route to the corresponding cyclopentane in the axinellimines that would be applicable to the synthesis of the revised structure of palau'amine. See: Starr, J. T, Koch, G, Carreira, E. M. J. Am. Chem. Soc. 2000, 122, 8793
    • Carreira has developed a route to the corresponding cyclopentane in the axinellimines that would be applicable to the synthesis of the revised structure of palau'amine. See: Starr, J. T.; Koch, G.; Carreira, E. M. J. Am. Chem. Soc. 2000, 122, 8793.
  • 25
    • 33845471758 scopus 로고    scopus 로고
    • For a Diels-Alder reaction of 3-chloro-2-nitroacrolein, see: Hoffman, J. M.; Phillips, B. T.; Cochran, D. W. J. Org. Chem. 1984, 49, 193.
    • For a Diels-Alder reaction of 3-chloro-2-nitroacrolein, see: Hoffman, J. M.; Phillips, B. T.; Cochran, D. W. J. Org. Chem. 1984, 49, 193.
  • 30
    • 37549036872 scopus 로고    scopus 로고
    • Exo/endo-selectivity varied from 0.8 to 1.1:1.0 when using toluene, dichloromethane, chloroform, acetone, acetonitrile, nitromethane, tert-butyl alcohol, or water as solvent. No obvious correlation of diastereoselectivity to solvent dielectric constant was observed. For a full table of results, see the Supporting Information.
    • Exo/endo-selectivity varied from 0.8 to 1.1:1.0 when using toluene, dichloromethane, chloroform, acetone, acetonitrile, nitromethane, tert-butyl alcohol, or water as solvent. No obvious correlation of diastereoselectivity to solvent dielectric constant was observed. For a full table of results, see the Supporting Information.
  • 33
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    • Gaussian Inc, Wallingford, CT
    • Frisch, M. J.; et al. Gaussian 03, revision C.02, Gaussian Inc., Wallingford, CT 2004.
    • (2004) Gaussian 03, revision , Issue.C.02
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  • 34
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    • All transition states were characterized by frequency calculations and shown to have a single negative eigenvalue
    • All transition states were characterized by frequency calculations and shown to have a single negative eigenvalue.
  • 35
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    • Charge analysis, using the CHelpG method (Breneman, C. M.; Wiberg, K. B. J. Comput. Chem. 1990, 11, 361), indicated a charge buildup of +0.31 on the diene.
    • Charge analysis, using the CHelpG method (Breneman, C. M.; Wiberg, K. B. J. Comput. Chem. 1990, 11, 361), indicated a charge buildup of +0.31 on the diene.
  • 36
    • 37549068702 scopus 로고    scopus 로고
    • Control experiments on several Diels-Alder adducts showed no sign of reversibility. In combination with the fact that the reactions are exothermic, the cycloadditions were assumed to be under kinetic control
    • Control experiments on several Diels-Alder adducts showed no sign of reversibility. In combination with the fact that the reactions are exothermic, the cycloadditions were assumed to be under kinetic control.
  • 37
    • 37549029941 scopus 로고    scopus 로고
    • α,β-unsaturated thiocarbonyls are known to be excellent dienes. See: Boger, D. L. Comprehensive Organic Synthesis; Trost, B. M.; Fleming, I.; Paquette, L. A., Eds.; Pergamon: Oxford 1991; 5, pp 451-512.
    • α,β-unsaturated thiocarbonyls are known to be excellent dienes. See: Boger, D. L. Comprehensive Organic Synthesis; Trost, B. M.; Fleming, I.; Paquette, L. A., Eds.; Pergamon: Oxford 1991; Vol. 5, pp 451-512.
  • 38
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    • See Supporting Information for synthesis of 22
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  • 39
    • 37549070082 scopus 로고    scopus 로고
    • Cycloadditions were generally devoid of side products. Isolated yields were difficult to obtain for hydantoin and thiohydantoin dienophiles due to consistent comigration of unreacted dienophile and cycloadduct upon silica gel chromatography. Pure cycloadducts were obtained either by exhaustive cycloaddition in the presence of an excess of cyclopentadiene or by accepting losses on chromatography. See Supporting Information for details on individual compounds
    • Cycloadditions were generally devoid of side products. Isolated yields were difficult to obtain for hydantoin and thiohydantoin dienophiles due to consistent comigration of unreacted dienophile and cycloadduct upon silica gel chromatography. Pure cycloadducts were obtained either by exhaustive cycloaddition in the presence of an excess of cyclopentadiene or by accepting losses on chromatography. See Supporting Information for details on individual compounds.
  • 40
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    • Higher temperatures resulted in thermal Boc deprotection
    • Higher temperatures resulted in thermal Boc deprotection.
  • 41
    • 37549032287 scopus 로고    scopus 로고
    • 2O) in the DFT calculations using the standard PCM method did not alter significantly either relative reactivity between dienophiles nor exo/endo selectivity.
    • 2O) in the DFT calculations using the standard PCM method did not alter significantly either relative reactivity between dienophiles nor exo/endo selectivity.
  • 54
    • 37549026988 scopus 로고    scopus 로고
    • Glendening, E. D, Reed, A. E, Carpenter, J. E, Weinhold, F. NBO, version 3.1
    • Glendening, E. D.; Reed, A. E.; Carpenter, J. E.; Weinhold, F. NBO, version 3.1.
  • 55
    • 37549039239 scopus 로고    scopus 로고
    • C=O 71-2 kcal/mol (thiohydantoin), 74.8 kcal/mol (hydantoin).
    • C=O 71-2 kcal/mol (thiohydantoin), 74.8 kcal/mol (hydantoin).
  • 56
    • 37549037652 scopus 로고    scopus 로고
    • Evans has noted the increased dienophilicity of thiazolidine thionyl acrylates compared to oxazolidinyl acrylates in copper-catalyzed Diels-Alder reactions, although in that case the difference in rates was attributed to the greater affinity of sulfur-based dienophiles for CuII Lewis acids. See ref 25b
    • II Lewis acids. See ref 25b.
  • 66
    • 37549055228 scopus 로고    scopus 로고
    • A referee noted the possibility for a C-H⋯O interaction between the methylene of cyclopentadiene and carbonyl oxygens in the exo-transition states. Weak C-H⋯O interactions were observed in NBO calculations on exo-15, exo-17, and exo-20 transition states. However, the interaction was no stronger in the hydantoin and thiohydantoin transition states than for the oxazolone. Thus, while it may lead to some overall stabilization of the exo-transition states, it does not account for the higher selectivity observed with hydantoins and thiohydantoins
    • A referee noted the possibility for a C-H⋯O interaction between the methylene of cyclopentadiene and carbonyl oxygens in the exo-transition states. Weak C-H⋯O interactions were observed in NBO calculations on exo-15, exo-17, and exo-20 transition states. However, the interaction was no stronger in the hydantoin and thiohydantoin transition states than for the oxazolone. Thus, while it may lead to some overall stabilization of the exo-transition states, it does not account for the higher selectivity observed with hydantoins and thiohydantoins.
  • 68
    • 37549004562 scopus 로고    scopus 로고
    • DFT calculations predict similar selectivity and reactivity for E-β-chloromethylene hydantoin and thiohydandtoin dienophiles, suggesting that our approach might be extended to access the chloride stereochemistry of 1b and the axinellamines.
    • DFT calculations predict similar selectivity and reactivity for E-β-chloromethylene hydantoin and thiohydandtoin dienophiles, suggesting that our approach might be extended to access the chloride stereochemistry of 1b and the axinellamines.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.