立 体 発 散 的 ス キ ッ プ ジ エ ン 合 成 法の 開 発 と マ ダ ン ガ ミ ン 類 の 網 羅 的全 合 成

A skipped diene（1,4-diene）is an important structural motif found in a variety of biologically active natural products. We report the stereodivergent method, consisting of hydroboration of allenes and the Migita-Kosugi-Stille coupling, which allows for access to all four possible stereo-isomers of the skipped dienes. The hydroboration of allenes is especially useful because both E-allylic and Z-allylic alcohols are obtained by simply changing the organoborane reagent. While use of 9-BBN provides E-allylic alcohols as thermodynamic products, the reaction with HB（Sia）₂ gives Z-allylic alcohols as kinetic products. The developed method was successfully applied to the unified total synthesis of madangamine alkaloids.