Amphiphilic Bis-7r-allylpalladium

It is well-established that 7r-allylpalladium is electrophilic, and no reaction with electrophiles has been observed. However, there is an evidence that bis-7r-allylpalladium (172), generated in situ, could be amphiphilic. Typically, formation of the 2-substituted 3,6-divinylpyran (175) by the reaction of butadiene with aldehyde can be explained by the amphiphilic nature of the bis-7r-allylpalladium 173 generated in situ as an intermediate, which reacts with the electrophilic carbon and the nucleophilic oxygen in the aldehyde as shown by 174 [86]. As a similar reaction, piperidone is obtained by the reaction of butadiene with isocyanate [87]. The reaction of allyltributylstannane (176), allyl chloride and benzalmalononitrile (177) in the presence of PdCl2(Ph3P)2 (3 mol %) afforded the diallylated product 178 in high yield. 

The reaction is explained by the in situ formation of bis-7r-allylpalladium (172), which is amphiphilic and reacts with 177 [88]. It is known that the reaction of the allylstannane 176 with aldehydes proceeds under rather severe conditions. Facile formation of the homoallyl alcohol 179 at room temperature in the presence of a Pt or Pd catalyst is explained by the nucleophilic nature of bis-7c-allylplatinum or -palladium generated in situ as an intermediate [89]. 

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