After inspection of the X-ray crystallographic anal-of mitomycin A (la) and albomitomycin A (2), an efficient chemical conversion of la to isomitomycin A (3) via 2 was accomplished in 68% overall yield. First, la was converted to (8aS)-8a-bromoalbomitomycin A (4b) in 89% yield, which was reduced with tributyltin hydride and AIBN to give 2 in 85% yield. Second, the C4a-N4 bond of 2 was selectively cleaved under hydrogenolysis conditions, and ...