Hydrogen Bonding Patterns in a Series of 3-Spirocyclic Oxindoles

Access to spirocyclic oxindoles via N-heterocyclic carbene-catalyzed reactions of enals and oxindole-derived α,β-unsaturated imines.

A diastereoselective access to β-lactam fused spirocyclic oxindoles and related compounds bearing all carbon spiro centers is described. This N-heterocyclic carbene-catalyzed process employed challenging β,β-disubstituted α,β-unsaturated imines to react with enals.

Alkaloid inspired spirocyclic oxindoles from 1,3-dipolar cycloaddition of pyridinium ylides.

Cycloaddition reactions between pyridinium ylides and 3-alkenyl oxindoles that proceed in high yield and with very good regio- and diastereoselectivity are reported. The resulting cycloadducts have the same stereochemistry of biologically active oxindole alkaloids, such as strychnofoline.

Highly diastereoselective one-pot synthesis of spirocyclic oxindoles through intramolecular Ullmann coupling and Claisen rearrangement.

Organocatalytic, Asymmetric [2+2+2] Annulation to Construct Six-Membered Spirocyclic Oxindoles with Six Continuous Stereogenic Centers

Lactols and cyclic hemiaminals were directly used in a one-pot organo/organo dual catalytic system induced [2+2+2] tandem reaction for the asymmetric construction of six-membered carbocycles. The enamine-based stereoselective Michael addition of lactols or cyclic hemiaminals to electron-deficient olefinic oxindole motifs provided chiral C4 components, which were further combined with triethylam...

Acceleration of an Aromatic Claisen Rearrangement via a Designed Spiroligozyme Catalyst that Mimics the Ketosteroid Isomerase Catalytic Dyad

A series of hydrogen-bonding catalysts have been designed for the aromatic Claisen rearrangement of a 1,1-dimethylallyl coumarin. These catalysts were designed as mimics of the two-point hydrogen-bonding interaction present in ketosteroid isomerase that has been proposed to stabilize a developing negative charge on the ether oxygen in the migration of the double bond.1 Two hydrogen bond donatin...