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Reactions of oxime dianions: Stereospecificity in alkylation

โœ Scribed by Michael E. Jung; Patricia A. Blair; John A. Lowe

Publisher
Elsevier Science
Year
1976
Tongue
French
Weight
223 KB
Volume
17
Category
Article
ISSN
0040-4039

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โœฆ Synopsis

Several years ago Hauser observed that treatment of aromatic ketoximes with two equivalents of strong base resulted in the formation of dianions which could be successfully alkylated on n carbon.L However, no information on the stereochemistry of the alkylated products was ever reported. We now wish to report total stereospecificity in the formation and alkylation of the a-carbon, oxygen-dianions of aliphatic ketoximes. Treatment of acetoxime 1 with two equivalents of n-BuLi in THF at OยฐC for 15 minutes resulted in the formation of exclusively the x dianion 2, which upon deuteration afforded cleanly compound 3.3 That the deuteration had occurred only on the s_yc methyl group was shown clearly by the NMR spectrum of 2 in benzene which exhibited a multiplet for the wmethyl group (6 1.70, 2H) and CH3. 2 BuLi ,C=N

๐Ÿ“œ SIMILAR VOLUMES

Alkylation of aldehyde oxime dianions
Alkylation of aldehyde oxime dianions
โœ Robert E. Gawley; Tibor Nagy ๐Ÿ“‚ Article ๐Ÿ“… 1984 ๐Ÿ› Elsevier Science ๐ŸŒ French โš– 88 KB

In contrast to an earlier report, aldoximes can be deprotonated to their dianions and alkylated in high yield. In 1976, Kofronl and JungL reported that ketone oximes could be deprotonated and alkylated regiospecifically syn to the oxime hydroxyl. In his report, Kofron noted that "attempts to alkyla