Hybrids of sugars and aromatics: A Pd-catalyzed modular approach to chromans and isochromans.
Herein we describe the synthesis of highly substituted chromans and isochromans using carbohydrates as starting materials. The key step of our synthetic approach is the annelation of the benzene moiety via a highly efficient Pd-catalyzed domino reaction. This powerful approach led to a small library of highly substituted chromans and isochromans by making use of a variety of different diynes and bromoglycals. We investigated several Pd-catalysts in order to improve the yields and to enlarge the scope of the domino reaction. Furthermore, we elucidated the mechanistic picture of the reaction with isotope-labelling experiments. Most probably the reaction proceeds via an oxidative addition followed by two carbopalladation steps and a final cyclization reaction.
Leibeling
Markus
M
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstr. 2, 37077 Göttingen, Germany.
Koester
Dennis C
DC
Pawliczek
Martin
M
Kratzert
Daniel
D
Dittrich
Birger
B
Werz
Daniel B
DB
D002241:Carbohydrates / Q000737:chemistry*; D002384:Catalysis; D002839:Chromans / Q000138:chemical synthesis*; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D007553:Isotope Labeling; D010165:Palladium; D054852:Small Molecule Libraries / Q000138:chemical synthesis
D002241:Carbohydrates; D002839:Chromans; D006841:Hydrocarbons, Aromatic; D054852:Small Molecule Libraries; D010165:Palladium