Department of Chemistry and Biochemistry, California State University, Northridge, 18111 Nordhoff Street, Northridge, California 91330, USA.
Org Lett. 2010 Apr 2;12(7):1580-3. doi: 10.1021/ol100315g.
Syntheses of the C-glycosyl flavone natural products aspalathin and nothofagin have been accomplished in eight steps from tribenzyl glucal, tribenzylphloroglucinol, and either 4-(benzyloxy)phenylacetylene or 3,4-bis(benzyloxy)phenylacetylene. The key step of the syntheses involves a highly stereoselective Lewis acid promoted coupling of 1,2-di-O-acyl-3,4,6-tribenzylglucose with tribenzylphloroglucinol, which gives rise to the corresponding beta-C-aryl glycoside in 30-65% yields.
C-糖苷黄酮天然产物 Aspalathin 和 Nothofagin 的合成都可以从三苄基葡萄糖、三苄基间苯三酚和 4-(苄氧基)苯乙炔或 3,4-双(苄氧基)苯乙炔出发,经过 8 步反应完成。合成的关键步骤涉及路易斯酸高立体选择性促进的 1,2-二-O-酰基-3,4,6-三苄基葡萄糖与三苄基间苯三酚的偶联,该偶联以 30-65%的收率得到相应的β-C-芳基糖苷。