The first totalsynthesis of herbimycin A (1), the benzoquinoid ansamycin antibiotic, has been accomplished by coupling two segments of the aliphatic ansa-chain 2 and the aromatic chromophore 3, elucidating the absolute stereochemistry.
regioselectively prepared from methyl α-D- and L-mannopyranosides through the reactions of the 3,4-anhydro-2-O-mesyl- and 3,4-anhydro-2-C-methylaltropyranoside derivatives with methylmagnesiumbromide and methylmagnesiumchloride.