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Stereoselective formation and rearrangement of morpholinium ylides derived from copper carbenoids

✍ Scribed by Kevin W. Glaeske; B.N. Naidu; F.G. West

Publisher: Elsevier Science
Year: 2003
Tongue: English
Weight: 153 KB
Volume: 14
Category: Article
ISSN: 0957-4166
DOI: 10.1016/s0957-4166(03)00095-8

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✦ Synopsis

Amino diazoacetoacetates 4a-e and 7a,b were prepared from readily available amino alcohols and subjected to copper-catalyzed carbene-transfer reaction. Substrates 4c-e furnished the morpholin-2-ones 5c-e in good yield via the corresponding cyclic ammonium ylides, albeit with poor diastereoselectivity. Substrates 4a,b failed to provide the corresponding morpholinones, perhaps as a result of steric congestion. Cyclic substrates 7a,b underwent conversion to bicyclic morpholinones 8 and 9 in good yield and with moderate to good diastereoselectivity. This result is rationalized via control of the transiently stereogenic ammonium center of the intermediate bicyclic ylides.

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