Qiu X,
Pierce JG.
*
NC State University, Raleigh, USA
Total Synthesis of Bipolamine I.
J. Am. Chem. Soc. 2022;
144: 12638-12641
DOI:
10.1021/jacs.2c06015
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.
