N-Phosphoryl imines react with oxygenated dienes in the presence of Lewis acids to provide either the formal aza-Diels-Alder adduct, or the acyclic Mannich-type addition product, depending upon the catalyst and work up used, which is in agreement with the hypothesis that these reactions are mediated by zwitterionic Lewis acid-complex intermediates, rather than a concerted cyclo-addition transition-state followed by hydrolytic ring opening. Stoichiometric asymmetric induction can be achieved using a zinc(II)binol complex, producing up 77% ee.
|Autori:||DI BARI L; GUILLARME S; HERMITAGE S; HOWARD JAK; JAY DA; PESCITELLI G; WHITING A; YUFITB DS|
|Titolo:||Lewis Acid-catalysed Aza-Diels–Alder versus Mannich Reactions of N-Diethyl Phosphoryl Imino Dienophiles with Oxygenated Dienes and Application of a Chiral Lewis Acid|
|Anno del prodotto:||2004|
|Digital Object Identifier (DOI):||10.1055/s-2004-817742|
|Appare nelle tipologie:||1.1 Articolo in rivista|