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Alkylierung in der 2-Stellung von (2S, 4R)- 4-Hydroxyprolin unter Retention

✍ Scribed by Theodor Weber; Dieter Seebach


Book ID
102254133
Publisher
John Wiley and Sons
Year
1985
Tongue
German
Weight
457 KB
Volume
68
Category
Article
ISSN
0018-019X

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✦ Synopsis


Alkylation in the 2‐Position of (2__S__, 4__R__)‐4‐Hydroxyproline with Retention of Configuration

O‐Acetyl‐4‐hydroxyproline (1b) is condensed with pivalaldehyde to give a single stereoisomer of the 2‐(tert‐butyl)‐4‐oxo‐3‐oxa‐1‐azabicyclo[3.3.0]oct‐7‐yl acetate (3). This is converted to the enolates 4 or 5, reactions of which with alkyl halides, aldehydes, and acetone (→6,9,10,11) are diastereoselective (lk‐1,3‐induction). Cleavage of the corresponding products furnishes the enantiomerically pure 2‐deuterio‐, 2‐methyl‐, 2‐allyl‐, and 2‐benzyl‐substituted 4‐hydroxyprolines 2a–2d.


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CC-Bindungsspaltung unter Inversion der
✍ Dr. Keith Ramig; Linda Brockunier; Patrice W. Rafalko; Dr. Leonid A. Rozov 📂 Article 📅 1995 🏛 John Wiley and Sons 🌐 English ⚖ 271 KB

ZUSCHRIFTEN [12] Fur 5 a und 5 b wurden ausschlieDlich irreversible Elektronentransferreaktionen elektrochemisch festgestellt: heispielsweise fur 5 a an Glaskohlenstoff-Elektrode in 1,2-Dimethoxyethdn mil (nBu),NPF, als Leitelektrolyt bei ED(oxl = + 0.86 V und