β-Silyl styrene as a dienophile in the cycloaddition with 3,5-dibromo-2-pyrone for the total synthesis of (±)-pancratistatin.

A new synthetic route to (±)-pancratistatin was devised utilizing β-silyl styrene as a dienophile in the cycloaddition with 3,5-dibromo-2-pyrone. The TMS group incorporated in the cycloadduct permitted a facile elimination process for the eventual installation of the C(1)-OH function. Subsequent transformations including Curtius rearrangement and Bischler-Napieralski reactions completed the total synthesis of (±)-pancratistatin.

Total synthesis of (+/-)-galanthamine via a C3-selective Stille coupling and IMDA cycloaddition cascade of 3,5-dibromo-2-pyrone.

A new efficient synthetic route to (+/-)-galanthamine was devised by using a tandem C3-selective Stille coupling-IMDA cascade of 3,5-dibromo-2-pyrone as a key strategy.