A convenient method for construction of a (+/-)-2,3-disubstituted maleic an
hydride segment of antibiotic tautomycin is reported. The key steps involve
d in the synthesis are chemoselective condensation of diethyl malonate with
2-(bromomethyl)-3-methylmaleic anhydride (3) and regioselective NBS-bromin
ation of the maleic anhydride derivative 7.