General method for asymmetric synthesis of substituted 2,2′-biaryldiols via asymmetric desymmetrization of 2,2′,6,6′-tetrahydroxybiphenyl with l-menthone
作者:Toshiro Harada、Shinji Ueda、Tran Mai Thi Tuyet、Atsushi Inoue、Katsuhiro Fujita、Masahiro Takeuchi、Nobuhiro Ogawa、Akira Oku、Motoo Shiro
DOI:10.1016/s0040-4020(97)10094-1
日期:1997.12
Asymmetric desymmetrization of prochiral 2,2′,6,6′-biphenyltetrol by acetalization with l-menthone affords isomenthonide 5b of S-axial chirality. A variety of (S)-6,6′-dialkoxy-2,2′-biphenyldiols of high enantiomeric purities are synthesized by using 5b as an intermediate. Thus, etherification of the hydroxy groups of 5b followed by hydrolysis of the isomenthonide moiety give the corresponding 6,6′-dialkoxy-2
通过用1-薄荷酮进行缩醛化来对前手性2,2',6,6'-联苯四醇进行不对称脱对称,得到异丁烯酸酯5b的S-轴手性。通过使用5b作为中间体,合成了多种高对映体纯度的(S)-6,6'-二烷氧基-2,2'-联苯二醇。因此,将5b的羟基醚化,然后将异薄荷酸酯部分水解,得到相应的6,6'-二烷氧基-2,2'-联苯二醇(12)。5b与1,ω-二溴代烷烃的分子间环化,然后水解产生2,2'-联苯二醇13在6和6'位置带有亚烷基二氧基桥。的区域选择性官能化13导致3,3'-二甲基,二苯基,和二(TBS)衍生物经由氨基甲酸酯衍生物的锂化定向或通过区域选择性溴化反应要么取得13。还讨论了缩醛化反应中立体选择性的起源以及2,2'-联苯二醇的轴向手性的热稳定性。