Pd-Catalyzed Bis-cyclization/Dimerization Reactions of ω-Aminovinyl Halides
摘要:
Palladium is shown to catalyze the dimerization and cyclization of vinyl halides to generate pyrrolidine and piperidine dimers connected by a trans-ethylene bridge. The reaction tolerates a variety of N-alkyl substituents, including adamantyl. This remarkable dimerization reaction generates the skeleton of the alkaloid hyalbidone in a single step. A crossover experiment with a vinyl halide and a vinyl bromide is consistent with a Michael-type addition to a vinylpalladium cation to generate a Pd(0) alkylidene intermediate.
Carbenylative Amination and Alkylation of Vinyl Iodides via Palladium Alkylidene Intermediates
作者:Ilandari Dewage Udara Anulal Premachandra、Thi A. Nguyen、Chengtian Shen、Eugene S. Gutman、David L. Van Vranken
DOI:10.1021/acs.orglett.5b02820
日期:2015.11.6
palladium-catalyzed reactions involving insertion of alkylidenes with α-hydrogens undergo β-hydride elimination from alkylpalladium(II) intermediates to form alkenes. Vinyl iodides were shown to generate η3-allylpalladium intermediates that resist β-hydride elimination, preserving the sp3 center adjacent to the carbene moiety. Acyclic stereocontrol (syn/anti) for carbenylative amination and alkylation reactions was