A three-step route of converting allylsilanes to functionalized allenes was developed. Thermal decomposition of 1, 1-dibromo-2-(silylmethyl) cyclopropanes, which were quantitatively prepared by treatment of allylsilane derivatives with CHBr3/KO t Bu, afforded substituted 2-bromo-1, 3-butadienes with elimination of bromosilanes. The Pd-catalyzed reaction of the bromodienes with soft nucleophiles gave the allene derivatives. Previously ...