Desymmetrization and Switching of Stereoselectivity in Direct Organocatalytic Michael Addition of Ketones to 1,1-Bis(phenylsulfonyl)ethylene

作者：Chen Yan Ming; Lee Pei Hsun; Lin Jun; Chen Kwunmin^*

来源：European Journal of Organic Chemistry, 2013, (13): 2699-2707.

DOI：10.1002/ejoc.201201635

• Synthetic methods
• Michael addition
• Organocatalysis
• Asymmetric catalysis
• Enantioselectivity

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 using either camphor-derived pyrrolidine V or cinchonidine-derived primary amine VII as a catalyst. The absolute stereochemistry of the (2R,4R)-2-[2,2-bis(phenylsulfonyl)ethyl]-4-methylcyclohexanone (3a) and (2R,4R)-2-[2,2-bis(phenylsulfonyl)ethyl]-4-tert-butylcyclohexanone (3b) was confirmed by single-crystal X-ray structure analyses.

• 出版日期2013-5