Concise total synthesis of acylated phenolic glycosides vitexnegheteroin A and ovatoside D.

Starting from readily available vanillin and α-D-acetobromo glucose, two natural acylated phenolic glycosides vitexnegheteroin A and ovatoside D were synthesized for the first time in 4 steps with overall yields of 54% and 65%, respectively. The key steps involve the directly regioselective O-6 acylation of vanillin β-D-glucopyranoside with acyl chlorides, and simultaneous removal of the allyl protecting groups on the phenolic acid moiety and reduction of the aldehyde in the aglycon moiety by using Pd(PPh)3 -NaBH4 system in one pot.