Artículos de revistas
The stereochemistry of the addition of titanium enolates of N-propionyl-oxazolidin-2-ones to 5- and 6-membered N-acyliminium ions
Registro en:
Tetrahedron Letters. Pergamon-elsevier Science Ltd, v. 40, n. 15, n. 2891, n. 2894, 1999.
0040-4039
WOS:000079465500008
10.1016/S0040-4039(99)00398-6
Autor
Pilli, RA
Alves, CD
Bockelmann, MA
Mascarenhas, YP
Nery, JG
Vencato, I
Institución
Resumen
The stereochemistry of the addition of the N-propionyl titanium enolates 2a and 2b to 5- and 6-membered 2-ethoxycarbamates 1a-f was investigated. The addition proceeded stereoselectively to afford the corresponding (2S,1'S)-2-substituted pyrrolidines as the major diastereoisomer. Despite the lack of reactivity between 2-ethoxypiperidine 1b and N-propionyl titanium enolates 2a and 2b, less bulky carbamate groups on 2-ethoxypiperidines 1d and 1f restored reactivity and the corresponding 2-substituted piperidines were obtained in moderate to good yields although with poor diastereoselection (C) 1999 Elsevier Science Ltd. All rights reserved. 40 15 2891 2894