Synthetic Studies Directed toward the Assembly of the C-Glycoside Fragment of the Telomerase Inhibitor D8646-2-6
摘要:
GraphicsConstruction and characterization of the C-glycosidic moiety of telomerase inhibitor D8646-2-6 (1) are described. This is the first example of the C-glycosylation using electron-poor aromatics, 4-hydroxypyrone, as a glycosyl acceptor. The glycosylation reaction and base-promoted isomerization affords desired beta-C-glycoside in a 61% overall yield.
Synthetic Study on Telomerase Inhibitor, D8646-2-6: Synthesis of the Key Intermediate Using Sn(OTf)2 or Sc(OTf)3 Mediated Aldol-Type Reaction and Stille Coupling
The synthesis of the key intermediate (4) in the proposed route to D8646-2-6 is described. The aldol reaction of the carbohydrate-containing pyrone 7 with the aldehyde 6 was accomplished by using LiHMDS and Sc(OTf)3 or Sn(OTf)2. The stepwise dehydration reaction of the aldol adduct 14, followed by Stillecoupling with vinyl stannane 5 which contained phosphonate gave the desired 4.
GraphicsConstruction and characterization of the C-glycosidic moiety of telomerase inhibitor D8646-2-6 (1) are described. This is the first example of the C-glycosylation using electron-poor aromatics, 4-hydroxypyrone, as a glycosyl acceptor. The glycosylation reaction and base-promoted isomerization affords desired beta-C-glycoside in a 61% overall yield.