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Preparation of β2-Amino Acid Derivatives (β2hThr, β2hTrp, β2hMet, β2hPro, β2hLys, Pyrrolidine-3-carboxylic Acid) by Using DIOZ as Chiral Auxiliary

✍ Scribed by Francois Gessier; Laurent Schaeffer; Thierry Kimmerlin; Oliver Flögel; Dieter Seebach

Publisher
John Wiley and Sons
Year
2005
Tongue
German
Weight
201 KB
Volume
88
Category
Article
ISSN
0018-019X

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✦ Synopsis

The title compounds were prepared from valine-derived N-acylated oxazolidin-2-ones, 1 ± 3, 7, 9, by highly diastereoselective ( ! 90%) Mannich reaction ( 3 4 ± 6; Scheme 1) or aldol addition ( 3 8 and 10; Scheme 2) of the corresponding Ti-or B-enolates as the key step. The superiority of the -5,5-diphenyl-4-isopropyl-1,3oxazolidin-2-one× (DIOZ) was demonstrated, once more, in these reactions and in subsequent transformations leading to various t-Bu-, Boc-, Fmoc-, and Cbz-protected b 2 -homoamino acid derivatives 11 ± 23 (Schemes 3 ± 6). The use of w-bromo-acyl-oxazolidinones 1 ± 3 as starting materials turned out to open access to a variety of enantiomerically pure trifunctional and cyclic carboxylic-acid derivatives.

📜 SIMILAR VOLUMES

Enantioselective Preparation of 2-Aminom
Enantioselective Preparation of 2-Aminomethyl Carboxylic Acid Derivatives: Solving the β2-Amino Acid Problem with the Chiral Auxiliary 4-Isopropyl-5,5-diphenyloxazolidin-2-one (DIOZ). Preliminary Communication
✍ Dieter Seebach; Laurent Schaeffer; François Gessier; Pascal Bindschädler; Corinn 📂 Article 📅 2003 🏛 John Wiley and Sons 🌐 German ⚖ 296 KB 👁 1 views

## Abstract Multigram amounts of suitably protected __β__^2^‐amino acids with 17 of the 20 proteinogenic side chains are prepared by diastereoselective reactions of Li, B, or Ti enolates of the corresponding 3‐acyl‐4‐isopropyl‐5,5‐diphenyloxazolidin‐2‐ones (acyl‐DIOZ; **1**) with appropriate electr