ChemInform Abstract: The Stereochemical Dichotomy in Palladium(0)- and Nickel(0)-Catalyzed Allylic Substitution.

✍ Scribed by C. N. FARTHING; P. KOCOVSKY

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 40 KB
• Volume: 29
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199846036

✦ Synopsis

The Stereochemical Dichotomy in Palladium(0)-and Nickel(0)-Catalyzed Allylic Substitution.

-In contrast to the known inversion-inversion steric pathway of allylic esters like (I), the corresponding acetate (IV), containing a phosphinous amide moiety, gives on treatment with malonate (II) in the presence of Pd(0) catalyst a product (V) as result of a retention-inversion pathway by precoordination of the catalyst to the phosphino group rather than to the acetoxy leaving group. While stereochemical control is highly successful with cyclic substrates, it does not operate in acyclic series, as is shown for hexenes (VII) and (X). The Ni(0)-catalyzed reaction of ether (XII) with MeMgBr affords derivative (XV), which is consistent with a double retention pathway. The corresponding trans derivative (XVII) fails to react in the expected manner.