Efficient Synthesis of Lupane-Type Saponins via Gold(I)-Catalyzed Glycosylation with Glycosyl ortho-Alkynylbenzoates as Donors
摘要:
Glycosylation of the acid labile betulin and betulinic acid derivatives was achieved with glycosyl ortho-hexynyibenzoates as donors under the catalysis of PPh3AuNTf2; this enabled the efficient synthesis of lupane-type saponins, as exemplified by the total synthesis of the proposed betulinic acid trisaccharide from Bersama engleriana.
Gold(I)-Catalyzed Glycosylation with Glycosyl<i>ortho</i>-Alkynylbenzoates as Donors: General Scope and Application in the Synthesis of a Cyclic Triterpene Saponin
coupling with the poorly nucleophilic amides gives satisfactory yields. Moreover, excellent α‐selective glycosylation with a 2‐deoxysugar donor and β‐selective sialylation have been realized. Application of the present glycosylation protocol in the efficient synthesis of a cyclic triterpene tetrasaccharide have further demonstrated the versatility and efficacy of this new method, in that a novel chemoselective
Efficient Synthesis of Lupane-Type Saponins via Gold(I)-Catalyzed Glycosylation with Glycosyl <i>ortho</i>-Alkynylbenzoates as Donors
作者:Yan Li、Jiansong Sun、Biao Yu
DOI:10.1021/ol202232v
日期:2011.10.21
Glycosylation of the acid labile betulin and betulinic acid derivatives was achieved with glycosyl ortho-hexynyibenzoates as donors under the catalysis of PPh3AuNTf2; this enabled the efficient synthesis of lupane-type saponins, as exemplified by the total synthesis of the proposed betulinic acid trisaccharide from Bersama engleriana.