K01-0509 B is a novel natural product which contains a carbamoylated cyclic guanidine. Our asymmetric total synthesis features a Sharpless
asymmetric epoxidation and a stereocontrolled construction of the cyclic guanidine via an asymmetric nitroaldol reaction, followed by
intramolecular SN2 cyclization. These reactions allowed the cyclic guanidine and the adjacent hydroxy group to be assembled, facilitating the
asymmetric total synthesis and determination of the absolute stereochemistry of K01-0509 B.