Lindström UM, Somfai P. Aza-[3,3]-Claisen enolate rearrangement in vinylaziridines: stereoselective synthesis of mono-, di-, and trisubstituted seven-membered lactams.
Chemistry 2001;
7:94-8. [PMID:
11205031 DOI:
10.1002/1521-3765(20010105)7:1<94::aid-chem94>3.0.co;2-m]
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Abstract
Several 2,3-disubstituted vinylaziridines have been N-acylated and subjected to LiHMDS in THF at -78 degrees C. Upon warming to room temperature, the resulting amide enolates underwent a highly stereoselective [3,3]-sigmatropic rearrangement to give mono-, di-, and trisubstituted seven-membered lactams in good yields. The scope and limitations of the process have been investigated by using variously substituted vinylaziridines. A kinetically controlled process proceeding through a six-membered boatlike transition state assembly has been invoked to explain the stereochemical outcome of the reaction.
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