Stereoselective Synthesis of 3-Alkylideneoxindoles by Palladium-Catalyzed Cyclization Reaction of 2-(Alkynyl)aryl Isocyanates with Organoboron Reagents
A palladium(0)/monophosphine catalystpromotes a cyclization reaction of 2-(alkynyl)aryl isocyanates with organoboron reagents to produce stereodefined 3-alkylideneoxindoles. The alkynyl and isocyanato groups undergo oxidative cyclization with Pd(0) to form an oxapalladacycle intermediate. Subsequent transmetalation and reductive elimination afford the product.
Stereoselective Synthesis of 3-(1-Cyanoalkylidene)oxindoles by Palladium-catalyzed Cyclization Reaction of 2-(Alkynyl)aryl Isocyanates with Copper(I) Cyanide
A palladium-catalyzed cyclization reaction of 2-(alkynyl)-aryl isocyanates with copper(I) cyanide provides an efficient method for the stereoselective synthesis of (Z)-configured 3-(1-cyanoalkylidene)oxindoles.