Synthesis of vicenin-1 and 3, 6,8- and 8,6-di-C-β-d-(glucopyranosyl-xylopyranosyl)-4′,5,7-trihydroxyflavones using two direct C-glycosylations of naringenin and phloroacetophenone with unprotected d-glucose and d-xylose in aqueous solution as the key reac

Vicenin-3 was synthesized from naringenin via a short five-step reaction, which included two regioselective direct C-glycosylations with d-glucose and d-xylose (yields: 22% and 30%, respectively) as the key reactions for a total yield of 4.4%. Vicenin-1 was also synthesized from phloroacetophenone via a 10-step reaction, including the same glycosylation described above, for a total yield of 2.7% with a vicenin-3 yield of 1.7%.