Enantioselective Synthesis of cis-1,2-Disubstituted Cyclopentanes and Cyclohexanes by Suzuki-Miyaura Cross-Coupling and Iridium-Catalyzed Asymmetric Hydrogenation
作者:Andreas Schumacher、Marcus G. Schrems、Andreas Pfaltz
DOI:10.1002/chem.201102650
日期:2011.11.25
using phosphinomethyloxazolines as ligands. Asymmetric hydrogenation of analogous cyclopentene derivatives, prepared by Suzuki–Miyaura cross‐coupling, proved to be more difficult and proceeded with lower enantioselectivities of up to 88 % ee. The synthetic potential of this cross‐coupling/asymmetric‐hydrogenation strategy was demonstrated by an enantioselective route to chiral hexahydrofluorenones.
通过Suzuki-Miyaura将2-溴-1-环己烯甲醛或2-羰甲氧基-1-环己烯-1-基三氟甲磺酸酯与芳基硼酸酯的交叉偶联制备了一系列1,2-二取代的环己烯衍生物。这些四取代的环状烯烃经过Ir催化的不对称氢化反应。通过使用膦基甲基恶唑啉作为配体,以这种方式以高收率获得了具有高对映选择性和非对映选择性(高达> 99%ee,> 99% 顺式)的顺-1-甲氧基甲基-2-芳基环己烷 。Suzuki-Miyaura交叉偶合制备的类似环戊烯衍生物的不对称氢化被证明更困难,并且对映体选择性较低,最高可达88% ee。这种交叉偶联/不对称氢化策略的合成潜力通过手性六氢芴酮的对映选择性途径得到证明。