Total Synthesis of Indolizidine Alkaloid (±)-Bipolamine I

Key words

(±)-bipolamine I - indolizidine alkaloids - ring-closing metathesis - Barton–McCombie deoxygenation - samarium(II) iodide

Significance

Pierce and Qiu report the first total synthesis of (±)-bipolamine I. The polypyrrole-containing subclass of indolizidine alkaloids is active against a variety of Gram-positive and -negative bacterial pathogens.

Comment

Cycloheptenol N is accessed in nine steps from acid A. The sequence features allylation of I with K, followed by ring-closing metathesis of L. MnO₂ oxidation of N results in formation of bridged ether O, and treatment with SmI₂ leads to hemi­acetal Q. A final Barton deoxygenation affords (±)-bipolamine I.

Publication History

Article published online:
20 September 2022