A Mannich reaction of deprotonated, highly enantioenriched α,α-disubstituted N-tert-butanesulfinyl ketimines with isatin-derived ketimines was developed to prepare 3-amino-3-substituted oxindoles bearing an acyclic quaternary stereogenic carbon substituted with two sterically similar… Click to show full abstract
A Mannich reaction of deprotonated, highly enantioenriched α,α-disubstituted N-tert-butanesulfinyl ketimines with isatin-derived ketimines was developed to prepare 3-amino-3-substituted oxindoles bearing an acyclic quaternary stereogenic carbon substituted with two sterically similar groups. The excellent stereocontrol of the deprotonation enabled the formation of metalloenamine intermediates with stereodefined geometry, while the precise facial selectivity of the C-C bond formation allowed the construction of contiguous quaternary and tetrasubstituted stereocenters with excellent stereoselectivity.
Journal Title: Organic letters
Year Published: 2022
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