“…The tubulysins are among the most potent cytotoxic compounds ever discovered from Nature. − Their mechanism of action involves depolymerization of microtubules with disintegration of the cytoskeleton as a consequence. − Isolated from the myxobacteria Archangium gephyra and Angiococcus disciformis , , these natural products elicited intense research efforts directed toward their total synthesis, analogue design and synthesis, and biological investigations as part of anticancer drug discovery and development programs. − Thus, total syntheses of the naturally occurring tubulysins A, B, C, D, − G, I, U ( Tb46 , Figure ), ,− and V ( Tb45 , Figure ) ,− and pretubulysin D ( PTb-D43 , Figure ), , as well as numerous analogues, have been accomplished. − From the latter, N 14 -desacetoxytubulysin H ( Tb1 , Figure ) is distinguished for its methyl, instead of the acyl methyl, substituent on N14 of tubulysins A–I ,− , and its high potency. , We have recently published a total synthesis of N 14 -desacetoxytubulysin H ( Tb1 , Figure ) and several of its analogues (e.g., Tb32 ,…”