Palladium-catalyzed hydrostannations of allenes and 1,6-diynes, a facile route to useful synthetic intermediates

grantor: University of TorontoThe palladium catalyzed hydrostannations of allenes and 1,6-diynes were studied. In the former case, the use of Pd(OH)$\sb2$/C as catalyst afforded vinyl stannanes as the major products. The use of soluble catalysts in the hydrostannation of allenes led to allyl stannanes as mixtures of stereoisomers. A variety of 1,6-diynes, when treated with a variety of palladium catalysts, underwent a hydrostannation-cyclization sequence to produce 1,2-dialkylidenecyclopentanes with (Z)-tributylstannyl moieties. The presence of phosphine ligands was found to inhibit the hydrostannation-cyclization, with less than 15% of desired product formation observed when ligands were used.M.Sc