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On the Regiochemistry of Nucleophilic Attack on 2-Halo π-Allyl Complexes. 4. The Effect of Silver Acetate and Nucleophile Concentrations in Competitive Nucleophilic Attack with Malonate and Phenoxide Nucleophiles

2003; American Chemical Society; Volume: 68; Issue: 10 Linguagem: Inglês

10.1021/jo034119c

1520-6904

Michael G. Organ, Elena A. Arvanitis, Stephen J. Hynes,

Chemical Synthesis and Analysis

2,3-Dibromo-1-propene or its allyl carbonate analogue are ionized under Pd catalysis to generate the 2-bromo Pd-pi-allyl complex (triphenylphosphine ligand), which alkylates with malonate nucleophile at the terminal position. The presence of acetate ion in the reaction mixture results in some malonate attack being redirected to the central carbon. The acetate ion can come from the ionization of 1-acetoxy-2-bromo-2-propene or by the addition of silver acetate to the reaction mixture. The addition of phenoxide ion to the reaction also causes the same regiochemical phenomena, although harder anions such as methoxide exert no such effect.