Structural study of a new antitumor antibiotic, kazusamycin.

Oxabicyclo[3.2.1]oct-6-enes as Templates for the Stereoselective Synthesis of Polypropionates: Total Synthesis of Callystatin A and C19-epi-Callystatin A

“…The structure of the marine polyketide callystatin A (1) was reported by Kobayashi and co-workers in 1997 1 and was followed shortly thereafter by the confirmation of its relative and absolute configuration. 2 Callystatin A is one of several structurally related polyketide natural products that display potent and diverse biological activities that include the anguinomycins, 3 kazusamycin, 4 leptofuranins, 5 leptomycins 6 and leptolstatin. 7 Callystatin A has been the target of significant synthetic research interest including total syntheses published by the research groups of Kobayashi, 8 Crimmins, 9 Smith, 10 Kalesse, 11 Marshall,12 and Enders.…”

Asymmetric Total Synthesis of Callystatin A: Asymmetric Aldol Additions with Titanium Enolates of Acyloxazolidinethiones

“…A number of highly cytotoxic polyketides, including the anguinomycins, leptofuranins, leptomycin, and kazusamycin, having similar gross chemical structures have been isolated from Streptomyces strains. Recently, a structurally related polyketide, callystatin A 1 , was isolated from the marine sponge, Callyspongia truncata , in the Nagasaki Prefecture .…”

First Total Synthesis of the Antitumor Compound (−)-Kazusamycin A and Absolute Structure Determination

“…These important biological activities, as well as an interesting structural feature, attracted our attention toward its total synthesis. Although a unique planar structure, including two types of dienes ( E , E and E , Z ), α,β-unsaturated δ-lactone, and a hydroxymethyl side chain, has been proposed, − neither its absolute nor relative configuration was determined. Several cytotoxic natural products with similar structures, e.g., callystatin A, leptomycin B, , and delactonmycin, have also been isolated, and their absolute configurations were recently elucidated by their total syntheses. − At the beginning of our synthetic studies together with elucidation of absolute configuration of kazusamycin A, we proposed structure 1 , shown in Figure , by analogy to leptomycin B.…”