Chromium-Mediated Asymmetric Synthesis of Both Enantiomers of Acetoxytubipofuran
作者:E. Peter Kündig、Rita Cannas、Mundruppady Laxmisha、Liu Ronggang、Sylvie Tchertchian
DOI:10.1021/ja029957n
日期:2003.5.1
enantioselective and diastereoselective dearomatization sequences starting from the benzaldehyde chromiumtricarbonyl 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
Chromium-Mediated Dearomatization: Application to the Synthesis of Racemic 15-Acetoxytubipofuran and Asymmetric Synthesis of Both Enantiomers
作者:E. Peter Kündig、Mundruppady S. Laxmisha、Rita Cannas、Sylvie Tchertchian、Liu Ronggang
DOI:10.1002/hlca.200590078
日期:2005.5
major diastereoisomer or the unusual product with inversion of configuration (see Table). For the synthesis of the (−)-enantiomer (R,R)-2 of 15-acetoxytubipofuran, an enantioselective dearomatization in the presence of a chiral diether ligand was implemented (Scheme 7), while the (+)-enantiomer (S,S)-2 was obtained via a diastereoselective dearomatization of an arene-bound chiral imine auxiliary (Scheme 8)