Alkene derivatives asymmetric Heck reactions

The chiral substituted 1,3-dioxepine derivative 231 has been prepared in 96% ee (50% conversion) by an asymmetric Heck reaction with the alkene 229 and the aryl triflate 230 [01OL161 ]. 

Palladium/silver-catalyzed Heck reactions have usually involved vinyl or aryl halides and alkenes, but these reaction conditions were also extended to allenes. Indeed, Zenner and Larock65 showed that simple alkyl allenes readily reacted with aryl and vinyl iodide derivatives in the presence of palladium acetate or chloride and silver phosphate. Moreover, the reaction could be rendered asymmetric using chiral ligands the best one was a bisoxazolidine derivative (Scheme 10.37). 

The enantioselective synthesis of optically active butanedioic acid derivatives is of interest as they are important intermediates of pharmaceuticals [67] and building blocks for rennin inhibitors [68]. These products are formed by the bis-alkoxycarbo-nylation of alkenes (Scheme 3.5), a reaction that was first reported by Heck in the early 1970s [42]. However, the first asymmetric version of this reaction was described more than 20 years later [69]. 

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