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Volumn , Issue 8, 2006, Pages 1386-1389

Convenient multigram synthesis of (R)-homopipecolic acid methyl ester

Author keywords

amino ester; Fractional crystallization; Michael additions; Piperidines; Stereoselective synthesis

Indexed keywords

ADDITION REACTIONS; CRYSTALLIZATION; ESTERS; STEREOCHEMISTRY; SYNTHESIS (CHEMICAL);

EID: 33646249406     PISSN: 00397881     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-2006-926419     Document Type: Article
Times cited : (7)

References (38)
  • 1
    • 33646268052 scopus 로고    scopus 로고
    • note
    • According to a Beilstein search; for some examples see references 2-7.
  • 25
    • 0029004264 scopus 로고
    • For some examples of enantioselective Michael additions of lithiated derivatives of 4 to α,β-unsaturated esters, see: (a) Davies, S. G.; Fenwick, D. R. J. Chem. Soc., Chem. Commun. 1995, 1109.
    • (1995) J. Chem. Soc., Chem. Commun. , pp. 1109
    • Davies, S.G.1    Fenwick, D.R.2
  • 28
    • 33646270766 scopus 로고    scopus 로고
    • note
    • (d) Ref. 9a.
  • 30
    • 33646229681 scopus 로고    scopus 로고
    • note
    • In the presence of two equivalents of (5)-4 and no additional base, compound 5 was obtained in a slightly improved yield (86%), but with a decreased diastereomeric ratio (67:33).
  • 31
    • 33646260813 scopus 로고    scopus 로고
    • note
    • The analogous cyclization of the tosyloxy derivative of 3 gave comparable results; nevertheless this route was less efficient - the tosyl derivative was prepared in a lower yield (73% from 2).
  • 32
    • 33646264191 scopus 로고    scopus 로고
    • note
    • For a related cyclization of an ω-iodo enoate, see ref. 2.
  • 34
    • 33646237703 scopus 로고    scopus 로고
    • note
    • Mesylate (E)-3 was synthesized from (E)-2, which was accessible by distillation of (E/Z)-2, see ref. 23.
  • 35
    • 33646271020 scopus 로고    scopus 로고
    • note
    • The crude product can also be purified by distillation (bp 75-85 °C, 0.02 mbar) through a Vigreux column (10 cm). Even though the lower boiling fractions were enriched with the minor diastereomer (S.S)-5, satisfactory separation of the two diastereomers was not achieved.
  • 36
    • 33646269622 scopus 로고    scopus 로고
    • note
    • There is just a short filtration through a pad of silica gel prior to the fractional crystallization.
  • 37
    • 33646266629 scopus 로고    scopus 로고
    • note
    • All fractions boiling below 70 °C/0.1 mbar were discarded: fractions boiling at 71-75 °C/0. 1 mbar contained mainly (Z)-2, fractions boiling at 92-96 °C/0. 1 mbar provided pure (E)-2.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.