Practical Synthesis of a<i>C</i>-Glycosyl Flavonoid via<i>O</i>→<i>C</i>Glycoside Rearrangement
作者:Toshihiro Kumazawa、Kazuhito Ohki、Mitsuo Ishida、Shingo Sato、Jun-ichi Onodera、Shigeru Matsuba
DOI:10.1246/bcsj.68.1379
日期:1995.5
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 boron trifluoride 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。