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Volumn 65, Issue 37, 2009, Pages 7837-7851

The dienolate aldol reaction of (E)-N-crotonoyl C(4)-isopropyl SuperQuat: asymmetric synthesis of α-vinyl-β-hydroxycarboxylic acid derivatives and conversion to α-ethylidene-β-hydroxyesters (β-substituted Baylis-Hillman products)

Author keywords

Asymmetric synthesis; Baylis Hillman; Dienolate aldol; SuperQuat

Indexed keywords

CARBOXYLIC ACID DERIVATIVE; ESTER DERIVATIVE; PROPANE;

EID: 68249093845     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tet.2009.07.004     Document Type: Article
Times cited : (18)

References (88)
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    • SuperQuat 11 was also isolated in 9% yield.
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    • Within the crystal lattice for compound 17 intermolecular hydrogen bonding is observed between the C(3′)-hydroxyl groups and the C(1′)-carbonyl groups.
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    • note
    • 1H NMR coupling constant analysis with 51 and 52 displaying diagnostic coupling constants of 3.6 and 4.0 Hz, respectively between the C(2′)H and C(3′)H protons, indicative of a syn-configuration. Furthermore, recrystallisation of the minor diastereoisomeric product of the reaction with isobutyraldehyde allowed the syn-relative configuration of the minor aldol product 52 to be unambiguously determined by X-ray crystallographic analysis, with the absolute (4S,2′R,3′S)-configuration assigned relative to the known (S)-configuration of the C(4)-stereogenic centre. Within the crystal lattice for compound 52 intermolecular hydrogen bonding is observed between the C(3′)-hydroxyl groups and the C(1′)-carbonyl groups.{A figure is presented} Chem3D representation of the single crystal X-ray structure of 52 (some H atoms have been omitted for clarity).
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    • Within the crystal lattice for compound 22 intermolecular hydrogen bonding is observed between the C(3′)-hydroxyl groups and the C(2)-carbonyl groups, whereas for compound 23 intermolecular hydrogen bonding is observed between the C(3′)-hydroxyl groups and the C(1′)-carbonyl groups.
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    • note
    • No aldol products were isolated upon reaction with pivalaldehyde, presumably due to its steric bulk precluding reaction.
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    • In each case, β,γ-unsaturated 12 was isolated (typically in ∼20% yield), along with small amounts (<5%) of SuperQuat auxiliary 11.
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    • 1H NMR spectrum of the crude reaction mixture and the pure product).
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* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.