title: Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins.
abstract: Various Mitsunobu conditions were investigated for a series of flavonolignans (silybin A, silybin B, isosilybin A, and silychristin A) to achieve either selective esterification in position C-23 or dehydration in a one-pot reaction yielding the biologically important enantiomers of hydnocarpin D, hydnocarpin and isohydnocarpin, respectively. This represents the only one-pot semi-synthetic method to access these flavonolignans in high yields.
authors.affiliation: Pharmazeutische und Medizinische Chemie, Institut für Pharmazie und Lebensmittelchemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany; College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, P. R. China.
authors.forename: Guozheng
authors.initials: G
authors.lastname: Huang
authors.affiliation: Pharmazeutische und Medizinische Chemie, Institut für Pharmazie und Lebensmittelchemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Schramm
authors.affiliation: Lehrstuhl für Pharmazeutische Biologie, Institut für Pharmazie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Heilmann
authors.affiliation: Centre of Biotransformation and Biocatalysis, Institute of Microbiology, Czech Academy of Sciences, Videnska 1083, Prague 4, CZ-14220, Czech Republic.
authors.forename: David
authors.initials: D
authors.lastname: Biedermann
authors.affiliation: Centre of Biotransformation and Biocatalysis, Institute of Microbiology, Czech Academy of Sciences, Videnska 1083, Prague 4, CZ-14220, Czech Republic.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Křen
authors.affiliation: Pharmazeutische und Medizinische Chemie, Institut für Pharmazie und Lebensmittelchemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Decker
keywords: Mitsunobu; dehydration; flavonoid; hydnocarpin; silybin