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A new chiral auxiliary in enantioselective hydrogenations: (—)-dihydrovinpocetine. Hydrogenation of ethyl pyruvate. II

✍ Scribed by A. Tungler; T. Máthé; K. Fodor; R.A. Sheldon; P. Gallezot

Book ID
103997607
Publisher
Elsevier Science
Year
1996
Tongue
English
Weight
597 KB
Volume
108
Category
Article
ISSN
1381-1169

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✦ Synopsis

A vinca-type synthetic alkaloid: ( -)-dihydrovinpocetine functions as a chiral auxiliary in the enantioselective hydrogenation of the C=O group of ethyl pyruvate. Various catalysts, supports, solvents have been screened. The effect of modifier's concentration, acetic acid additive and of combined modifiers (+ dihydro-cinchonidine and -cinchonine) is described. The highest optical yield (30%) is obtained with a Pt on alumina catalyst. Mechanistic considerations and comparison with the known Pt/cinchona system have been made.

📜 SIMILAR VOLUMES

New chiral modifiers in enantioselective
New chiral modifiers in enantioselective heterogeneous catalytic hydrogenation of ethyl pyruvate over Pt/Al2O3: chiral amino alcohols derived from piperidine
✍ A Solladié-Cavallo; C Marsol; F Garin 📂 Article 📅 2002 🏛 Elsevier Science 🌐 French ⚖ 64 KB

New chiral and enantiopure erythro and threo 1,2-amino-alcohols 4a and 4b have been shown to accelerate the heterogeneous catalytic hydrogenation of ethyl pyruvate as much as cinchonidine does (with 77-100% conversion within 2 h). A diastereo dependence of the enantioselectivity is clearly observed