Halogenated Allyl Alcohol Derivatives ‐ Versatile Electrophiles for Palladium‐Catalyzed Allylic Alkylations

Abstract

Brominated and iodinated allylic substrates can be subjected to palladium‐catalyzed allylic alkylation of amino acid and peptide ester enolates. The incorporation of a vinylic halide functionality into the allylic substrate allows a direct modification of the allylated peptide via cross coupling chemistry. Therefore, the direct introduction of a vinylhalide side chain into a peptide is an interesting alternative to the stannylallylation/halogenation approach. However, the haloallylation is not as trivial as normal allylic alkylations, because the incorporation of a second, competitive electrophilic center into the allyl moiety requires careful optimization of the reaction conditions.