The First Catalytic Allylic Substitutions

After these initial results by Tsuji, this elementary step was incorporated into a catalytic process by Hata and co-workers at Toray Industries and by Atkins and co-workers at Union Carbide. These groups reported reactions of allylic phenyl ethers, allylic alcohols, and allylic acetates with carboxylates, alcohols, primary and secondary amines, and methyl acetoacetate catalyzed by Pd(0) complexes and precursors to Pd(0) complexes (Equation 20.3). - After these initial reports, early developments focused on reactions of soft carbanions derived from 3-dicarbonyl compounds, cyanoesters, and related compounds containing two electron-withdrawing groups attached to the nucleophilic carbon. Although these reactions occur with allylic halides in the absence of a catalyst, these reactions are greatly accelerated by palladium catalysts. Thus, the palladium catalyst allows these reactions to occur under mild conditions with allylic acfetates, which are more accessible than allylic halides, and with selectivities that are altered by the metal catalyst. 

With this ability to control selectivity, palladium-catalyzed substitution chemistry was developed into an enantioselective process. In the early enantioselective reactions, a racemic or achiral allylic electrophile underwent substitution with a soft carbon nucleophile to 

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