One-Pot Generation of C≡X Bonds from Methyl 2-Siloxycyclopropane­carboxylates: Simple Syntheses of Functionalized Nitriles and Alkynes

Starting from methyl 2-siloxycyclopropanecarboxylates simple and efficient one-pot procedures are described that lead to beta-cyanoesters and methoxycarbonyl-substituted terminal alkynes. The prepared functionalized alkynes were subjected to typical transformations such as [3+2] cycloaddition providing triazole derivatives, Sonogashira coupling, Au-catalyzed hydrophosphorylation or a copper-catalyzed coupling of methyl diazoacetate furnishing alkyne 14 and allene derivative 15. The Pauson-Khand reaction of the enyne 4c afforded a diastereomeric mixture of methyl 5-oxohexahydropentalen-2-carboxylate 16 in moderate yield.