Aza-Diels-Alder reaction between N-aryl-1-oxo-1H-isoindolium ions and tert-enamides: Steric effects on reaction outcome.
The synthesis of 5-substituted 6,6a-dihydroisoindolo[2,1-a]quinolin-11(5H)-ones via [4 + 2] imino-Diels-Alder cyclization from N-aryl-3-hydroxyisoindolinones and N-vinyl lactams under Lewis acid-catalysed anhydrous conditions is reported. Reactions of N-(2-substituted-aryl)-3-hydroxyisoindolinones with N-vinylpyrrolidone under identical conditions resulted in the formation of 2-(2-substitued-aryl)-3-(2-(2-oxopyrrolidin-1-yl)vinyl)isoindolin-1-one analogues indicating steric hinderance as the cause of deviation. The probable mechanism of the reaction based on the results from X-ray crystallography and molecular modelling is discussed.
Department of Chemistry, Acadia University, Wolfville, NS, Canada.
Amitabh
A
Jha
Department of Chemistry, Acadia University, Wolfville, NS, Canada.
Ting-Yi
TY
Chou
Department of Chemistry, Acadia University, Wolfville, NS, Canada.
Zainab
Z
Aljaroudi
Department of Chemistry, Acadia University, Wolfville, NS, Canada.
Bobby D
BD
Ellis
Department of Chemistry, Dalhousie University, Halifax, NS, Canada.
T Stanley
TS
Cameron
Diels–Alder; N-acyliminium ion; alkene addition; cyclization; inverse electron demand; tert-enamide