Synthesis and determination of absolute stereochemistry of Gosodesmine

Gosodesmine ( 1 ) is an indolizidine alkaloid that was isolated and structurally determined in 2020, but its absolute stereochemistry remained unknown. We synthesized 1 from Boc-L-β-homoproline ( 4 ) and compared the optical rotations of our synthesized Gosodesmine with the natural Gosodesmine. Based on the reported values, we determined that the absolute stereochemistry of 1 is the R -configuration. Additionally, we demonstrated using HPLC that racemization did not occur during our synthesis. • We synthesized (8a S )-(+)-Gosodesmine ( 1 ) from Boc-L-β-homoproline ( 4 ). • By measuring the optical rotation of our synthesized (8a S )-(+)-Gosodesmine ( 1 ), we determined that the absolute configuration of natural Gosodesmine is the R -configuration. • We also demonstrated that racemization did not occur during our synthesis.