Asymmetric Synthesis of Axially Chiral Biaryls via Desymmetrization of 2,2‘,6,6‘-Tetrahydroxybiphenyl Using 1,4-Di-<i>O</i>-benzyl-<scp>l</scp>-threitol as a Chiral Template
作者:Tran Mai Thi Tuyet、Toshiro Harada、Kazuyuki Hashimoto、Masanori Hatsuda、Akira Oku
DOI:10.1021/jo991364g
日期:2000.3.1
Sequential etherification of 2,2',6,6'-tetrahydroxybiphenyl (1) with 1,4-di-O-benzyl-L-threitol under Mitsunobu conditions gives desymmetrized biphenyldiol 9 of S-axial chirality exclusively. Cyclization of 9 with 1,omega-dibromoalkanes followed by removal of the chiral auxiliary yields (S)-2,2'-biphenyldiols 14 with alkylenedioxy bridges at the 6 and 6' positions. (S)-6,6'-Dialkyl- and -diphenyldiols
在Mitsunobu条件下,将2,2',6,6'-四羟基联苯(1)与1,4-二-O-苄基-L-苏糖醇顺序醚化,可以得到具有S轴手性的脱对称联苯二醇9。用1,ω-二溴代烷烃环化9,然后除去在6和6'位置带有亚烷基二氧基桥的手性辅助化合物(S)-2,2'-联苯二醇14。通过双(三氟甲磺酸酯)衍生物17与有机锌试剂的Pd(0)催化的交叉偶联,以有效的方式获得了(S)-6,6'-二烷基-和-二苯基二醇20。双(三氟甲磺酸酯)17还用作不对称合成轴向手性联苯二羧酸23,三联苯甲酸28,内酯26和内酰胺30的中间体。