The C-glycosylation of 2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl fluoride and 2-acetylphloroglucinol 3,5-bis(alkyl ether) in the presence of borontrifluoride etherate as an activator stereoselectively gave the β-C-glucoside in a good yield via O → C glycoside rearrangement. Subsequently, aldol condensation of the C-glucoside with benzaldehyde afforded the corresponding β-C-glucosyl chalcone in a good
2,3,4,6-四-O-苄基-α-D-吡喃葡萄糖基氟和2-乙酰间苯三酚3,5-双(烷基醚)在三氟化硼醚化物作为活化剂存在下的C-糖基化立体选择性地得到通过 O → C 糖苷重排,β-C-糖苷的产率很高。随后,C-葡萄糖苷与苯甲醛的羟醛缩合以良好的收率提供相应的β-C-葡萄糖基查耳酮。
Synthetic Study on Carthamin: Problem and Solution for Oxidative Dearomatization Approach to Quinol C-Glycoside
作者:Ken Ohmori、Keisuke Suzuki、Taiki Hayashi
DOI:10.1055/s-0035-1562511
日期:——
Synthetic study on carthamin, a naturalredpigment, is described. Attempts at the construction of the key quinol C-glycoside structure by oxidative dearomatization of C-glycosyl phenols were hampered by the competing cleavage of the C1–C2 bond in the sugar moiety. By employing the 2-O-acetyl protection, the projected reaction proceeded smoothly, giving the desired products in good to excellent yields
Aryl<i>C</i>-Glycosides from<i>O</i>-Glycosyltrichloroacetimidates and Phenol Derivatives with Trimethylsilyl Trifluoromethanesulfonate (TMSOTf) as the Catalyst
作者:Jürgen-Andreas Mahling、Richard R. Schmidt
DOI:10.1055/s-1993-25859
日期:——
The reaction of O-(2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl) trichloracetimidate (1), as glycosyl donor with phenol and naphthol derivatives 2a-d and 2f-h, as glycosyl acceptors, furnished in the presence of catalytic amounts of TMSOTf the corresponding o-hydroxyaryl C-β-D-glucopyranosides 3a-d, f-h regio- and stereoselectively. The less reactive 4-methoxyphenol (2e), α-naphthol (2i), the hydroxy substituted coumarines 2j, k and the flavone 21 afforded under these conditions O-glycosides 5e, i-l. Hydrogenolytic O-debenzylation of 3a,b,d afforded compounds 4a,b,d.
Aryl C-glycosylation of phenols with glycosyl trifluoroacetimidates
作者:Yuwen Li、Guo Wei、Biao Yu
DOI:10.1016/j.carres.2006.08.022
日期:2006.11
Aryl C-glycosylation of a variety of phenols with glycosyl trifluoroacetimidates in the presence of TMSOTf was examined, leading to the corresponding ortho-hydroxyaryl C-glycosides in variable yields. (c) 2006 Elsevier Ltd. All rights reserved.
Mahling, Juergen-Andreas; Schmidt, Richard R., Liebigs Annalen, 1995, # 3, p. 467 - 470