Allylation Reaction Of Oxindoles And Its Application

Prenylated indoles and spirocyclic oxindoles are important motifs found in a variety of natural products and pharmaceuticals with diverse biological activities.This paper focuses on the synthesis of such interesting scaffolds via the regioselectivity of allylation reaction of oxindoles.The synthetic utility of the methodologies is verified by formal synthesis of the flustramine family alkaloid?±?-debromoflustramine E and its analogs.The first chapter describes the methods for the allylation of oxindoles in recent years.The second chapter describes the zinc mediated?-regioselective prenylation of isatin-derived imines.The protocol enables an efficient access to various3-amino-3-?-prenyl-oxindoles from cheap and readily available chemicals in good to excellent yields.The obtained prenylated adduct can be further manipulated to other more complicated derivatives through cyclization or oxidatiton.The third chapter describes the zinc mediated?-regioselective prenylation of3-acylidene-oxindole with prenyl bromide using CeCl₃ as the catalyst.The new transformation tolerates a wide range of 3-acylidene-oxindoles,providing an easy access to a variety of functionalized 3-prenylated oxindoles.The synthetic utility of the approach is verified by synthesis of fused-indoline-heterocycle.In the fourth chapter describes formal synthesis of the flustramine family alkaloid?±?-debromoflustramine E by using commercially available N-Bn isatin as a starting material,following aldol condensation,dehydration,[3,3]rearrangement,oximation,Beckmann rearrangement,hydrolysis and amination.In the fifth chapter describes oxindole-fused-spirotetrahydrofurochroman scaffolds via[4+2]cycloaddition using 3-cinnamyl-3-hydroxy-2-oxindoles and2-hydroxysalicylaldehyde,providing a novel method for the synthesis of pharmaceutically active molecules containing such frameworks.All of the compounds obtained by the above mentioned reactions were characterized by ¹H NMR,¹³C NMR and HR-MS.Some compounds were characterized by X-ray.