Stereoselective Synthesis of Tetrahydrofuran Lignans via BF<sub>3</sub>·OEt<sub>2</sub>-Promoted Reductive Deoxygenation/Epimerization of Cyclic Hemiketal: Synthesis of (−)-Odoratisol C, (−)-Futokadsurin A, (−)-Veraguensin, (+)-Fragransin A<sub>2</sub>, (+)-Galbelgin, and (+)-Talaumidin
作者:Hyoungsu Kim、Ceshea M. Wooten、Yongho Park、Jiyong Hong
DOI:10.1021/ol7016388
日期:2007.9.1
A versatile route to the synthesis of 2,5-diaryl-3,4-dimethyltetrahydrofuran lignans, (-)-odoratisol C (1), (-)-futokadsurin A (2), (-)-veraguensin (3), (+)-fragransin A2 (4), (+)-galbelgin (5), and (+)-talaumidin (6), is described. Central to the synthesis of the lignans is BF(3) x OEt(2)-promoted deoxygenation/epimerization of the hemiketal 9a followed by stereoselective reduction of the oxocarbenium
合成2,5-二芳基-3,4-二甲基四氢呋喃木脂素,(-)-香豆酚C(1),(-)-Futokadsurin A(2),(-)-veraguensin(3),(描述了+)-fragransin A2(4),(+)-galbelgin(5)和(+)-talaumidin(6)。木酚素合成的核心是BF(3)x OEt(2)促进半缩醛9a的脱氧/表观电子化,然后立体选择性还原氧碳鎓离子中间体8a,b。