N,N¢-Diaryl-2,5-dioxopiperazines 8 and 9, related to the amino acid alanine, are easily obtained by self-cyclocoupling of 2-bromopropananilides 7. The cis-(R,R) or cis-(S,S)/trans-(R,S) distribution is controlled, to varying extents, by starting either from a single enantiomer or racemate and by the promoter, aryl substituent, and solvent. 1H NMR spectra of the members of six diastereomeric couples and X-ray structures of representative products are reported.
Stereoselective synthesis of N,N-diaryl-2,5-dioxopiperazines from homochiral or racemic 2-bromopropananilides
D'ANGELI, Ferruccio;MARCHETTI, Paolo;RONDANIN, Riccardo;BERTOLASI, Valerio
1996
Abstract
N,N¢-Diaryl-2,5-dioxopiperazines 8 and 9, related to the amino acid alanine, are easily obtained by self-cyclocoupling of 2-bromopropananilides 7. The cis-(R,R) or cis-(S,S)/trans-(R,S) distribution is controlled, to varying extents, by starting either from a single enantiomer or racemate and by the promoter, aryl substituent, and solvent. 1H NMR spectra of the members of six diastereomeric couples and X-ray structures of representative products are reported.File in questo prodotto:
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