Synthesis of 3-fluoroazetidines.

N-(Alkylidene or 1-arylmethylidene)-2-propenylamines were regiospecifically functionalized to novel N-(alkylidene or 1-arylmethylidene)-3-bromo-2-fluoropropylamines, which were proven to be excellent precursors for 3-fluoroazetidines.

A New Synthesis of 2-Methyleneaziridines.

A new synthetic route leading to 2-methyleneaziridines has been developed by base-induced 1,2-dehydrobromination of 2-(bromomethyl)aziridines. Several base-solvent pairs did not lead to 2-methyleneaziridines. Only potassium tert-butoxide in tetrahydrofuran afforded 2-methyleneaziridines in competition with the substitution products, i.