A convenient method for construction of a (±)-2,3-disubstituted maleic anhydride segment of antibiotic tautomycin is reported. The key steps involved in the synthesis are chemoselective condensation of diethyl malonate with 2-(bromomethyl)-3-methylmaleic anhydride (3) and regioselective NBS-bromination of the maleic anhydride derivative 7.
Tautomycin - antifungal antibiotic - regioselective NBS-bromination - part structure synthesis