Asymmetric synthesis of the A-ring part of ciguatoxin by the strategy based on diastereoselective hydroboration and ring closing metathesis

Asymmetric synthesis of the A-ring part of a marine toxin ciguatoxin (CTX1B ) was achieved by the strategy based on ring closing metathesis (RCM), wher e introduction of the C5 asymmetric center was performed by diastereocontro lled hydroboration of a vinyl ether moiety.