The enantiocontrolled total synthesis of (-)-haouamine B pentaacetate was accomplished via an optically active indane-fused β-lactam, which was prepared by a newly developed Friedel-Crafts reaction. Subsequent cleavage of the β-lactam and an intramolecular McMurry coupling reaction provided the core indane-fused tetrahydropyridine, which led to the elucidation of the structure, as proposed by Trauner and Zubía.

Scope and limitations of the debenzylation conditions for aryl benzyl ether, which was developed during our synthetic studies on yatakemycin, were investigated. The chemoselective debenzylation proceeds at low temperature with a combination of BCl 3 and pentamethylbenzene as a cation scavenger in the presence of various functional groups.

Synthetic studies on haouamine B are described. The characteristic indenotetrahydropyridone skeleton was constructed by intramolecular Friedel-Crafts alkylation of mesyloxy b-lactam derivative and intramolecular McMurry coupling as key processes.