Stable 5‐Substituted Cyclopentadienes for the Diels–Alder Cycloaddition and their Application to the Synthesis of Palau'amine

Putting the brakes on a hydride shift: The incorporation of a 2-silyloxy group increases both the stability and reactivity of 5-substituted cyclopentadienes, thus facilitating their preparation and use (see scheme; Bz=benzyl, TBS=tert-butyldimethylsilyl). This approach has been applied to the synthesis of the E ring in the marine alkaloid palau'amine.