Studies toward the Synthesis of Chartelline C

Chartelline
C, a marine alkaloid, possesses a unique core scaffold
including indolenine β-lactam and imidazole moieties linked
by an unsaturated 10-membered ring. A new synthetic approach for the
construction of the indolenine β-lactam
was planned, based on the inherent reactivity of chartelline A with
NaOMe, triggered by bromination of bromoenamide, and proceeding through
an N-acyl imine. However, the N-acyl
imine intermediate was not observed. Instead, the corresponding bromoindolenine
was obtained, which led to the desired indolenine β-lactam in
92% yield.