Simple and stereoselective syntheses of aplysinopsins and their analogs fro
m either methyl 2-[(2,2 disubstituted ethenyl)amino]-3-(dimethylamino)prop-
2-enoates or 5-[(dimethylamino)methylidene]imidazolidine-2,4-diones 20 are
described. The structures of products are established by H-1 and C-13-NMR.
and NOESY spectroscopy, and X-ray crystal-structure analysis.