The first total synthesis of the marine antibiotic spiroxin A has been achieved for both enantiomeric forms. The discovery of two competing cascade processes triggered by two orthogonal stimuli, photo-irradiation or acid/base treatment, enabled the divergent conversion of a single chiral, nonracemic bis-quinone into both enantiomers of an advanced intermediate en route to both (-)- and (+)-spiroxin A. The mechanism of the enantiodivergence is discussed.
Keywords: cascade reactions; natural product synthesis; photoreactions; redox chemistry; spiroxin A.
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