Regioselective Silane-Terminated Intramolecular Heck Reaction with Alkenyl Triflates and Alkenyl Iodides

Abstract

One of the main problems of the Heck reaction using acyclic substrates which lead to Pd intermediates with β- and β′-hydrogens is the lack of selectivity in the formation of the double bond as the last step of the catalytic cycle. The use of allylsilanes as the alkene moiety permits control of the elimination step. Thus, the Pd0-catalysed reaction of 1a−c and 2 leads exclusively to the corresponding bicyclic compounds 11a−c. In contrast, reaction of 7 yields a mixture of 12a, (E)-12b and (Z)-12b.