Stereoselective synthesis of three-membered ring compounds via ylide routes

Three types of small ring compounds (epoxides, aziridines and cyclopropanes ) can be synthesized stereoselectively via ylide route. Among them, the ste reochemistry of vinyloxiranes, vinylaziridines, cyclopropylesters, amides a nd ketones can be tuned by the choice of reaction conditions and ylides wit h varying heteroatoms and ligands. Optically active epoxides and acetylenyl aziridines can be prepared via camphor-derived chiral sulfonium ylide route s.