Artículos de revistas
The stereochemistry of the addition of chlorotitanium enolates of N-acyl oxazolidin-2-ones to 5-and 6-membered N-acyliminium ions
Registro en:
Journal Of The Brazilian Chemical Society. Soc Brasileira Quimica, v. 12, n. 5, n. 634, n. 651, 2001.
0103-5053
WOS:000170611400006
10.1590/S0103-50532001000500007
Autor
Pilli, RA
Bockelmann, MA
Alves, CD
Institución
Resumen
The stereoselective addition of chiral and achiral titanium enolates derived from the corresponding N-acyl oxazolidin-2-ones to 5- and 6- membered N-acyliminium ions afforded 2-substituted pyrrolidines in moderate to good diastereoisomeric ratio (5:1 to 14:1) while lower diastereoselection was generally observed in the formation of the corresponding 2-substituted piperidines. The stereochemical outcome was found to be modulated by the nature of the cyclic N-acyliminium ion (5- or 6- membered) and of its carbamate and by the N-acyl group in the enolate precursor. The preferential lk approach seems to be dictated mainly by the minimization of non-bonding interactions between the N-acyl group in the chlorotitanium (IV) enolate and the carbamate and methylene groups in the cyclic N-acyliminium ion. 12 5 634 651