Synthetic Studies on Alotamide A: Construction of N-Demethylalotamide A

Abstract

Several approaches to the synthesis of cyclodepsipeptide natural product alotamide A are described, eventually affording a very advanced N-demethylated analogue of the targeted natural product. The difficulties found in our endeavors on the synthesis of alotamide A have allowed us to gather some valuable information regarding the most convenient synthetic step for each key transformation. The intramolecular Csp2−Csp2 Stille cross-coupling and the macrolactam formation were found to be reliable protocols for the final construction of the alotamide A skeleton.