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Chromium-Mediated Asymmetric Synthesis of Both Enantiomers of Acetoxytubipofuran

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journal contribution
posted on 2003-04-22, 00:00 authored by E. Peter Kündig, Rita Cannas, Mundruppady Laxmisha, Liu Ronggang, Sylvie Tchertchian
Both enantiomers of acetoxytubipofuran were synthesized using enantioselective and diastereoselective dearomatization sequences starting from the benzaldehyde chromium tricarbonyl complex. Following aldol condensation, a sequence involving Pd-catalyzed allylic substitution was used in the synthesis of the (−)-enantiomer, whereas the (+)-enantiomer was reached via an Eschenmoser−Claisen rearrangement. Chiroptical data show that a revision of the previously assigned absolute configuration of the natural product is required.