Unexpected Desilylative-alkylation of 3-O-tert-Butyl-dimethylsilyl Galangin

摘要

Biological activities of flavonoids have led to the creation of many therapeutic forms of plant flavonoids.Data on the chemical structures of a variety of flavonoids have been obtained, and the fundamental mechanisms of action of flavonoids as antioxidants, anu-inflammatories, cardiotonics, radioprotectors, antitumor agents and antiviral agents have been identified. However, little effort has been expended on synthetic flavonoid analogues presumably due to the difficulties in controlling the regiochemistry of the flavonoids. As a part of our ongoing efforts directed at the structure-activity relationship studies (SARs) of naturally occurring flavonoids, we have been interested in the regioselective alkylation of flavanones (naringenin, 1, Fig. 1) and flavones (apigenin, 2, Fig.1). Herein, we report our recent attempts on the regioselective alkylation of a flavonol, galangin (3, Fig. 1).