An organocatalytic domino thia-Michael/ aldol condensation reaction of a, b-unsaturated aldehydes with 1, 4-dithiane-2,5-diol catalyzed by chiral diphenylprolinol TMS ether has been developed, which provides a new practical and direct route to chiral dihydrothiophenes with high yields (up to 90%) and excellent enantioselectivities (up to > 99% ee). The catalytic mechanism of the domino reaction was further confirmed through the APCI-MS detection of proposed reaction intermediates.

Asymmetric Michael addition reactions of unmodified ketones to nitroalkenes were performed in PEGs catalyzed by novel pyrrolidinyl-thioimidazolium salts to give products in up to 97% yield and 99% enantioselectivity; ESI mass spectrometric detection for the first time gave evidence of the presence of the PEG-organocatalyst host-guest complex.

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Enantioselective syntheses O 0031Organocatalysts Wrapped Around by Poly(ethylene glycol)s (PEGs): A Unique Host-Guest System for Asymmetric Michael Addition Reactions. -Asymmetric Michael addition reactions of unmodified ketones (I) to nitroalkenes (II) are performed in polyethylene glycols catalyzed by novel thioimidazolium salts. ESI mass spectrometric detection gives for the first time evidence of the presence of a PEG-organocatalyst host-guest complex. Furthermore, the catalytic system is reusable simply by exctraction of the aldol products (III). -(XU, D. Q.; LUO, S. P.; WANG, Y. F.; XIA, A. B.; YUE, H. D.; WANG, L. P.; XU*