2-Allyl-4-piperidones, formation

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. 

In 2001, Magnus and co-workers reported a straightforward synthesis of racemic rhazinilam by initial construction of the pyrrole ring from a piperidone, Fig. (33) [154]. The sequential alkylation of piperidone 155 with iodoethane and allyl bromide furnished piperidone 156, having the requisite C-20 substitution of rhazinilam. After formation of the thiophenyl iminoether 157, A-alkylation with allyl bromide 158 furnished the corresponding iminium intermediate which underwent 1,5-... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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