Abstract
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. The direct organocatalytic desymmetrization was demonstrated for 4-substituted cyclohexanones by treatment with a vinyl sulfone in CHCl 3. The desired Michael adducts were obtained in high chemical yields and stereoselectivities (up to 97 % yield, 93 % ee). Enantiomeric products were obtained by using either a camphor-derived pyrrolidine or a cinchonidine-derived primary amine as a catalyst.
Original language | English |
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Pages (from-to) | 2699-2707 |
Number of pages | 9 |
Journal | European Journal of Organic Chemistry |
Issue number | 13 |
DOIs | |
Publication status | Published - 2013 May 1 |
Keywords
- Asymmetric catalysis
- Enantioselectivity
- Michael addition
- Organocatalysis
- Synthetic methods
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry