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Volumn 45, Issue 12, 2004, Pages 2597-2601

Lithium enolates from a (-)-quinic acid-derived cyclohexanone with a β-alkoxy leaving group: Regioselective preparation and evaluation of enolate stability towards β-elimination

Author keywords

( ) Quinic acid; Cyclohexanones; Deprotonation; Elimination reactions; Regiocontrol

Indexed keywords

8 [[TERT BUTYL(DIMETHYL)SILYL]OXYL] 2,3 DIMETHOXY 2,3 DIMETHYLHEXAHYDRO 1,4 BENZODIOXIN 6(5H) ONE; AZIDE; CYCLOHEXANONE DERIVATIVE; KETONE; LITHIUM DERIVATIVE; LITHIUM ENOLATE; LITHIUM HEXAMETHYLDISILAZIDE; QUINIC ACID; UNCLASSIFIED DRUG;

EID: 1542272312     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2004.01.148     Document Type: Article
Times cited : (13)

References (39)
  • 15
    • 1542347401 scopus 로고    scopus 로고
    • note
    • 9.
  • 16
    • 0028129050 scopus 로고
    • 3SiCl gave a 4:1 mixture of regioisomeric silyl enol ethers. In contrast, ketone 9 (with an axial β-silyloxy group) gave a single regioisomeric silyl enol ether under the same conditions. See: Boyer F.-D., Lallemand J.-Y. Tetrahedron. 50:1994;10443-10458.
    • (1994) Tetrahedron , vol.50 , pp. 10443-10458
    • Boyer, F.-D.1    Lallemand, J.-Y.2
  • 27
    • 1542287104 scopus 로고    scopus 로고
    • note
    • We are confident that the enolates from 1 and 2 form upon treatment with LHMDS at -78°C for 30 min since they have been trapped with a range of aldehydes to give the expected aldol adducts in 23-80% yields.
  • 28
    • 0033569971 scopus 로고    scopus 로고
    • For an example where others have previously encountered difficulty in eliminating a β-silyloxy group in a related cyclohexanone, see:
    • For an example where others have previously encountered difficulty in eliminating a β-silyloxy group in a related cyclohexanone, see: Hareau G., Koiwa M., Hanazawa T., Sato F. Tetrahedron Lett. 40:1999;7493-7496.
    • (1999) Tetrahedron Lett. , vol.40 , pp. 7493-7496
    • Hareau, G.1    Koiwa, M.2    Hanazawa, T.3    Sato, F.4
  • 31
    • 1542317287 scopus 로고    scopus 로고
    • note
    • An alternative explanation for the requirement of 2.10 equiv of LHMDS is as follows: if β-elimination of the enolate of 2 is slow and enone 1 is readily deprotonated then as enone 1 is formed, it could be deprotonated by the enolate of 2. In this way, 2.0 equiv LHMDS would be required to complete the elimination process. We are grateful to a referee for this suggestion.
  • 33
    • 1542347405 scopus 로고    scopus 로고
    • note
    • 2O. Majewski, M. Personal communication.
  • 38
    • 1542377145 scopus 로고    scopus 로고
    • note
    • 3J -values are ≤2.0 Hz and cannot be due to a trans-diaxial coupling that is, the adjacent oxygen substituent must be axial (OTBS group).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.