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The direct organocatalytic desymmetrization of cyclic meso -anhydrides was achieved by alcoholysis with nitroallylic alcohols. The reaction between primary nitroallylic alcohols and cyclic meso -anhydrides catalyzed by cinchonidine derived thiourea organocatalyst II (10 mol %) proceeded smoothly. The corresponding hemiesters were obtained in high chemical yields with high to excellent levels of stereoselectivity (up to 90% yield and 99% ee). On the other hand, the reversal of enantioselectivity was observed when an amino cinchonidine derivative ( III ) was used as the organocatalyst under the similar reaction conditions. This demonstrated an example of activation of the nucelophilic component in the desymmetrization of cyclic meso -anhydrides. [ABSTRACT FROM AUTHOR]

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 (2 R,4 R)-2-[2,2-bis(phenylsulfonyl)ethyl]-4-methylcyclohexanone ( 3a) and (2 R,4 R)-2-[2,2-bis(phenylsulfonyl)ethyl]-4- tert-butylcyclohexanone ( 3b) was confirmed by single-crystal X-ray structure analyses. [ABSTRACT FROM AUTHOR]

Further hydrolysis of the title intermediates provides tetrahydropyridines in high yields and with high diastereo- and enantioselectivities. [ABSTRACT FROM AUTHOR]

Hexahydropyridazine derivatives are synthesized by the entitled one-pot reaction sequence in high yields and good stereoselectivities. [ABSTRACT FROM AUTHOR]

An abstract of the article " Organocatalytic Desymmetrization of Cyclic meso-Anhydrides Through Enantioselective Alcoholysis with Functionalized Primary Nitroallylic Alcohols" by Y. M. Chen and colleagues is presented.

Camphor-derived pyrrolidine catalyst bearing a thiourea-group and cinchonidine-derived catalyst are used to prepare the enantiomeric ketosulfones with comparable yields and stereoselectivities. [ABSTRACT FROM AUTHOR]

The title synthesis succeeds in high yields, with high diastereoselectivities and excellent enantioselectivities. [ABSTRACT FROM AUTHOR]