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Volumn 47, Issue 37, 2008, Pages 7013-7017

Enantioselective oxazaborolidinium-catalyzed Diels-Alder reactions without CH·⋯O hydrogen bonding

Author keywords

Asymmetric catalysis; Density functional calculations; Lewis acids; Lewis bases; Transition states

Indexed keywords

ACIDS; CHEMICAL REACTIONS; COORDINATION REACTIONS; ENANTIOSELECTIVITY; ESTERS; HYDROGEN; ORGANIC COMPOUNDS;

EID: 84962384555     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200802002     Document Type: Article
Times cited : (39)

References (36)
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    • Angew. Chem. Int. Ed. 2005, 44, 1484-1487.
    • (2005) Angew. Chem. Int. Ed , vol.44 , pp. 1484-1487
  • 15
    • 84962350747 scopus 로고    scopus 로고
    • We find that SnCl4 is an excellent activator for Corey's oxazaborolidine 1a. Corey recently reported the use of AlBr3 as an activator for 1a.[4a] Control experiments demonstrate that triflimide-activated catalyst 1a·HNTf2 gives the same major enantiomer as does 1a·SnCl4 see the Supporting Information for details
    • 4 (see the Supporting Information for details).
  • 20
    • 84962440275 scopus 로고    scopus 로고
    • Justification for the choice of the level of theory is given in the Supporting Information. MP2/6-31G(d) single-point energies were also calculated but they gave inferior results compared to the MPW1K results (see the Supporting Information for details).
    • Justification for the choice of the level of theory is given in the Supporting Information. MP2/6-31G(d) single-point energies were also calculated but they gave inferior results compared to the MPW1K results (see the Supporting Information for details).
  • 23
    • 84962440270 scopus 로고    scopus 로고
    • Unless stated otherwise, the discussion refers to the PCM results
    • Unless stated otherwise, the discussion refers to the PCM results.
  • 24
    • 85022815549 scopus 로고    scopus 로고
    • Indeed, it has been shown that the association of an α,β-enal and a cognate oxazaborolidine catalyst is rapidly reversible on the NMR timescale: E. J. Corey, T.-P. Loh, T. D. Roper, M. D. Azimioara, M. C. Noe, J. Am. Chem. Soc. 1992, 114, 8290-8292.
    • Indeed, it has been shown that the association of an α,β-enal and a cognate oxazaborolidine catalyst is rapidly reversible on the NMR timescale: E. J. Corey, T.-P. Loh, T. D. Roper, M. D. Azimioara, M. C. Noe, J. Am. Chem. Soc. 1992, 114, 8290-8292.
  • 25
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    • [1]
    • [1]
  • 26
    • 84962394169 scopus 로고    scopus 로고
    • It turns out that for all systems investigated the most stable TS has both the smallest enthalpy and Gibbs free energy
    • It turns out that for all systems investigated the most stable TS has both the smallest enthalpy and Gibbs free energy.
  • 27
    • 84962440252 scopus 로고    scopus 로고
    • -1.
    • -1.
  • 29
    • 84962426557 scopus 로고    scopus 로고
    • Although the boron center may coordinate to the carbonyl oxygen atom lone pair, which is anti to the dienophile C=C; anti complexation is 5 kJ mol-1 less stable than syn complexation
    • -1 less stable than syn complexation.
  • 35
    • 84962457391 scopus 로고    scopus 로고
    • -1): 4 (6.4); 11 (0.3); 12 (8.7).
    • -1): 4 (6.4); 11 (0.3); 12 (8.7).
  • 36
    • 84962457388 scopus 로고    scopus 로고
    • 2Me group.
    • 2Me group.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.