Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
Chirality. 2012 Mar;24(3):215-22. doi: 10.1002/chir.21985. Epub 2012 Jan 25.
The synthesis of planar chiral strong Brønsted acid organocatalysts derived from [2.2]paracyclophane is described. Resolution was accomplished according to a modified protocol involving pseudo-ortho-substituted [2.2]paracyclophane-based sulfoxides for the synthesis of three new sulfonic acids. The first planar chiral phosphoric acid diester was obtained from the corresponding phenyl-substituted diol derived from enantiopure 4-bromo-12-hydroxy [2.2]paracyclophane. These new classes of catalysts were tested in an enantioselective Friedel-Crafts reaction as well as in a direct asymmetric Mannich reaction and gave yields of up to 93% and ee-values of up to 38%.
描述了源自[2.2]对环芳烷的平面手性强布朗斯特酸有机催化剂的合成。根据涉及对 pseudo-ortho-取代的[2.2]对环芳烷基砜的改良方案，实现了拆分，用于合成三种新的磺酸。第一个平面手性磷酸二酯是从相应的苯取代二醇获得的，该二醇由对映纯的 4-溴-12-羟基[2.2]对环芳烷衍生而来。这些新类别的催化剂在对映选择性傅克反应以及直接不对称曼尼希反应中进行了测试，最高产率为 93%，ee 值最高为 38%。
