Palladium Catalyzed Asymmetric Allylation of 3-OBoc-Oxindoles: An Efficient Synthesis of 3-Allyl-3-hydroxyoxindoles

Abstract

3-Allyl-3-hydroxyoxindoles were synthesized in very good enantio- (up to 97% ee) and diastereoselectivities (dr up to 7.6:1) with contiguous quaternary and tertiary stereogenic centers by employing tartrate derived bi(oxazoline) in Pd-catalyzed allylation of 3-OBoc-oxindole. Synthetic utility of 3-allyl-3-hydroxyoxindole was demonstrated by synthesizing a highly substituted spiro(oxindole-3,2'-tetrahydrofuran) derivative in good yield and stereoselectivity.

Recent advances in the asymmetric catalytic synthesis of chiral 3-hydroxy and 3-aminooxindoles and derivatives: Medicinally relevant compounds

“…Bis(oxazoline)-based ligands were tested in an asymmetric allylation of N-substituted-3-O-Boc-oxindoles with allyl acetates. The resulting 3-allyl-3-hydroxyoxindoles presented good enantioselectivities and diastereoselectivities (since a vicinal quaternary carbon center is formed) when prepared in the presence of the catalyst [Pd(h 3 -C 3 H 5 )Cl] 2 (2.5 mol%)/L18 (10 mol%) with N,O-bis(trimethylsilyl)acetamide (BSA) and KOAc as additive (Scheme 47) [169].…”

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

“…Kesavan and co-workers described that the Pd/bis(oxazoline) ( L1 ) complex can catalyze the asymmetric allylation of 3- O- Boc-oxindole, yielding the 3-allyl-3-hydroxyoxindoles in good yields (up to 93% yield) and with high enantioselectivities (up to 97% ee) and diastereoselectivities (up to 7.6:1 dr, Scheme 3 ) [ 15 ]. The best condition was 2.5 mol % of [Pd(η 3 -C 3 H 5 )Cl)] 2 , 10 mol % of L1 as the ligand and 10 mol % of KOAc as an additive, and 3 equiv of BSA ( N,O -bis(trimethylsilyl)acetamide).…”

Efficient Synthesis of Highly Functionalized Spirocarbocyclic Oxindoles through Hauser Annulation

“…As part of our ongoing interest in the development of new and efficient synthetic strategies for the synthesis of biologically important oxindole‐fused spiro heterocyclic systems and spiro carbocyclic systems, we planned to synthesize the spirocarbocyclic oxindole framework through the Hauser annulation of phthalides. There is no precedent in the literature for the use of oxindole‐based Hauser acceptors.…”