Stereocontrolled Total Synthesis of Amphidinolide X via a Silicon-Tethered Metathesis Reaction

Two esterifications and an RCM to create the challenging trisubstituted C12-C13 double bond were required in the total synthesis of amphidinolide X (1) reported here. Assembling the three fragments in this order, no RCM occurred or the process yielded mainly isomer Z. However, generating the E double bond first, by a new variant of a Si-tethered metathesis (using Schrock's catalyst), and carrying out the esterification and macrolactonization steps later, 1 was obtained exclusively.