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All‐Carbon‐Substituted Quaternary Carbon Atoms in Oxindoles by an Aerobic Palladium(II)‐Catalyzed Ring Closure onto Tri‐ and Tetrasubstituted Double Bonds
Author(s) -
Schiffner Julia A.,
Oestreich Martin
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201001526
Subject(s) - chemistry , regioselectivity , palladium , ring (chemistry) , electrophile , catalysis , quaternary carbon , medicinal chemistry , double bond , carbon fibers , organic chemistry , enantioselective synthesis , materials science , composite number , composite material
Oxidative palladium(II)‐catalyzed cyclization of α,β‐unsaturated amides derived from electron‐rich anilines is reported. The aerobic ring closure of tri‐ and tetrasubstituted alkenes yields oxindoles with congested all‐carbon‐substituted quaternary carbon atoms. The ring‐size selectivity is excellent. Selected unsymmetrically substituted arenes cyclize with perfect regioselectivity. Experimental evidence indicates that the mechanism is likely to involve Friedel–Crafts‐type electrophilic substitution rather than direct C–H bond activation.