A series of 10,13-disubstituted 16-membered macrolides was synthesized using nitroso Diels–Alder reactions of leucomycin A7. Despite the extensive constituent functionalities in leucomycin, the hetero cycloaddition reactions proceeded in a highly regio- and stereoselective fashion. Subsequent chemical modifications of the nitroso cycloadducts, including N–O bond reduction, were also conducted. Most leucomycin derivatives retained antibiotic profiles similar to leucomycin A7, and, in contrast to leucomycin itself, several exhibited moderate antiproliferative and cytotoxic activity.

An efficient procedure for the highly selective oxidation of leucomycines to the corresponding 16-membered 9- and 13-oxo macrolides using hypervalent iodinates is presented. Both the Dess-Martin periodinane (DMP) and polymer-bound 2-iodoxybenzoic acid (IBX) show clear advantages over the previously employed manganese dioxide. Key intermediates for a variety of further chemical derivatization methods (2a, 2b) are obtained in very good yields without the requirement of protecting groups.