Desymmetrization and Switching of Stereoselectivity in Direct Organocatalytic Michael Addition of Ketones to 1,1-Bis(phenylsulfonyl)ethylene
作者:Yan ming Chen、Pei-Hsun Lee、Jun Lin、Kwunmin Chen
DOI:10.1002/ejoc.201201635
日期:2013.5
The organocatalytic desymmetrization was demonstrated for 4-substituted cyclohexanones by treatment with a vinyl sulfone in the presence of an organocatalyst. The desired Michael adducts were typically obtained in high chemical yields and high to excellent stereoselectivities (up to 97 % yield, 93 % ee). An efficient desymmetrization method was developed for the synthesis of enantiomeric products by
通过在有机催化剂存在下用乙烯基砜处理 4-取代的环己酮证明了有机催化去对称化。所需的迈克尔加合物通常以高化学产率和高至极好的立体选择性(高达 97% 的产率,93% ee)获得。通过使用樟脑衍生的吡咯烷 V 或辛可尼定衍生的伯胺 VII 作为催化剂,开发了一种有效的去对称化方法来合成对映体产品。(2R,4R)-2-[2,2-双(苯磺酰基)乙基]-4-甲基环己酮(3a)和(2R,4R)-2-[2,2-双(苯磺酰基)乙基]的绝对立体化学]-4-叔丁基环己酮 (3b) 通过单晶 X 射线结构分析得到证实。