Abstract von Prof. Dr. Reinhard Brückner, Albert-Ludwigs-Universität Freiburg

The First Stereoselective Total Synthesis of a Dimeric (Naphthoquinono)pyrano-γ-lactone: (+)-γ-Actinorhodin

We accomplished the first total synthesis of an isomerically pure Naphthoquinopyrano-γ-lactone dimer – γ-actinorhodin – in 11 steps. It is the first stereoselective total synthesis of a naphthoquinonopyrano-γ- lactone dimer at all. Others who tried the same, obtained dimers which were diastereomeric mixtures or no dimer at all.

Two steps of our approach exploit pairs of peri-placed MeO groups as unusual selectivity controls. The respective MeO groups convey the steric bulk of a bromo or iodo substituent located ortho to a first MeO group as steric hindrance into the vicinity of another MeO group. This relay effect was indispensable for exerting (a) regiocontrol in an aromatic bromination and (b) diastereocontrol in an oxa-Pictet Spengler cyclization.

The absolute configuration of our target was established by the asymmetric Sharpless dihydroxylation of a β,γ-unsaturated ester. It provided the lactone moiety of a bromonaphthalene, which was poised to dimerize to the core of γ-actinorhodin by Suzuki couplings. The unsaturated ester stemmed from a Heck coupling of ethyl vinylacetate with a bromoiodonaphthalene. The latter was synthesized from 1,5-dihydroxynaphthalene via monoiodo-1,4,5,8-tetramethoxynaphthalene.

Curriculum Vitae von Prof. Dr. Reinhard Brückner

Born 5. 5. 1955 in Braunschweig

Schooling 1962-1974 in Darmstadt

Chemistry studies 1974-1980 LMU München

Dr. rer nat. 1984 with Prof. Dr. Rolf Huisgen

Postdoctoral studies 1984-85 with Prof. Paul A. Wender at Stanford University

Habilitation 1985-89 under the auspices of Prof. Dr. Reinhard Hoffmann at Philipps-Universität

Marburg

Professor of Organic Chemistry at Julius-Maximilians-Universität Würzburg 1991-1992

Professor of Organic Chemistry at Georg-August-Universität Göttingen 1992-1998

Professor of Organic Chemistry at Albert-Ludwigs-Universität Freiburg since 1998

Visiting Professorships: University of Wisconsin, Madison; Universidade de Santiago de Compostela,

Spain; Indiana University, Bloomington; Stellenbosch University, South Africa

ADUC award (1989)

Awardee of the Karl Winnacker foundation (1990)

Chemistry Award of the Academy of Science of Göttingen (1990)

Society of Synthetic Organic Chemistry Japan Lectureship (1996)

Literature Prize of the Foundation of the Chemical Industries (1998)

Novartis Chemistry Lectureship (2008)

2000-2004 and Elected Reviewer of the Study Section „Organic Chemistry“ of the

2004-2008 German Research Foundation (DFG)

2000-2004 and Elected Vice-President and President, respectively, of the

2004-2008 „Division of Organic Chemistry“ of the German Chemical Society (GDCh)

Research interests: natural product synthesis and the development of pertinent methodology

Teaching interests: author of a textbook both in German (“Reaktionsmechanismen”) and English

(“Organic Mechanisms”); co-author of a 2-volume laboratory course (“Praktikum Präparative

Organische Chemie")