The total synthesis of mitomycins via isomitomycin A is described. Key reactions are a Michael-type coupling reaction between chalcone (94)* and 5-ethylthio-2-trimethylsiloxyfuran, followed by an azido-olefin cyclization. The first route took 30 steps from 2,6-dimethoxytoluene in a overall yield of 6%. The improved second route contains 26 steps with overall yield of 10% from the same staring material. Resolution of an synthetic intermediate resulted in both (+)- and (−)-isomitomycin A (15). X-ray crystallographic analysis of an intermediate with known chiral auxiliary which led to the natural (−)-isomitomycin A unequivocally determined the absolute stereochemistry of mitomycins. ftn*Please refer to dissertation for diagrams.