Use of 8,8′-dihydroxy-1,1′-binaphthalene as a chiral auxiliary for asymmetric Diels-Alder cycloadditions
作者:Kiyoshi Tanaka、Naoyuki Asakawa、Mohammad Nuruzzaman、Kaoru Fuji
DOI:10.1016/s0957-4166(97)00474-6
日期:1997.11
The Diels-Alder reactions of unsymmetrical maleate 2 and fumarate 10 possessing axially chiral 8,8′-dihydroxy-1,1′-binaphthalene 1 with cyclopentadiene were investigated under various conditions in the presence of a Lewis acid. Both the diastereo- and endo/exo-selectivities depended on the Lewis acid used. A notably high level of diastereoselection was achieved with TiCl(OiPr)3 for the endo adduct
在路易斯酸的存在下,在各种条件下研究了具有轴向手性8,8'-二羟基-1,1'-联萘1的不对称马来酸酯2和富马酸酯10的Diels-Alder反应与环戊二烯的反应。非对映选择性和内/外选择性都取决于所用的路易斯酸。用TiCl(O i Pr)3作为马来酸酯的内加合物和SnCl 4达到了很高的非对映选择性。对于富马酸盐。结果表明,在这些环加成反应中,助剂的游离羟基在诱导高水平的非对映选择性中起着至关重要的作用。