✦ LIBER ✦
Reactions of lithium salts ofO-alkyl oximes with halogens: A highly stereoselective oxidative coupling of 5,6-dihydro-3-methyl-4H-1,2-oxazine
✍ Scribed by Shatzmiller, Shimon ;Lidor, Ramy ;Bahar, Eliezer ;Goldberg, Israel
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 605 KB
- Volume
- 1991
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Abstract
Lithiation of 5,6‐dihydro‐3‐methyl‐4__H__‐1,2‐oxazine (4) in an unpolar solvent system (hexane/THF) at −65°C followed by reaction with Cl~2~,Br~2~, or I~2~ affords cleanly and stereoselectively 6 (RS,RS) of which an X‐ray structure analysis is described. In contrast, attempts to couple the halogenated 1,2‐oxazine derivative 5c have given, under various reaction conditions, equal amouts of 6 and 8 (meso). A mechanism of this reaction is discussed.