Platinum(ll)-Catalyzed Intermolecular [3 + 2] Cycloaddition of Propadienyl Silyl Ethers and Alkenyl Ethers

摘要

The use of allenes as a three-carbon unit for [3 + n] cycloaddition reactions is relatively unexplored compared with [2 + n]-type reactions using allenes as a 2π unit. Representative examples of such transformation are the Lewis acid-promoted [3 + 2] cycloaddition reactions of allenylsilanes and the phosphine-triggered reactions of 2,3-butadienoates with electron-deficient alkenes, imines, aziridines, etc. On the contrary, transition-metal-catalyzed [3 + n] cycloaddition reactions had not been reported until recent reports of intramolecular [3 + 2] and [3 + 4] cycloaddition reactions, and to date there is still no report of an intermolecular reaction using the 1,2-propadiene moiety of allene derivatives as a three-carbon unit.