C-Glycosides are an important class of naturally occurring and synthetic bioactive products.1 In contrast to their O-analogues, C-glycosides are less vulnerable to metabolic processing, which has led to significant interest in their viability as drug candidates and inhibitors of carbohydrate processing enzymes.2
Interesting group of C-glycosides are bergenin-type C-glycosides, that have been isolated from variety of plants3 and numerous reports about their biological and pharmacological properties have been reported.4-5
Herein I report a mild Pd-catalyzed approach for the synthesis of various α- or β-C-glycosides starting from simple building blocks. The key step is Suzuki reaction of glucal or galactal boronates with different electron-rich halogen derivatives providing desired products under mild condition in excellent yields. I also found that our synthetic method is effective for the total synthesis of natural and unnatural bergenin-type C-glycosides in interesting overall yields. Details of our approach will be described.
Acknowledgement: This work was supported by the Grant Agency of the Czech Republic (grant No. P207/12/P713).
References
1. Hultin, P. G.: Curr. Top. Med. Chem. 2005, 5, 1299.
2. Lin H.-C., Yang W.-B.: Curr. Top. Med. Chem. 2005, 5, 1431.
3. Saijo R., Nonaka G., Chen I. S., Hwang T.-H.: Chem. Pharm. Bull. 1989, 37, 2940.
4. Piacente S., Pizza C., deTommasi N., Mahmood N.: J. Nat. Prod.1996, 59, 565.
5. Lim H.-K., Kim H.-S., Kim S.-H., Chang M.-J., Rhee G. S., Ch.: J. Arch. Pharm. Res. 2001, 24, 114.
