Study of the Michael addition of beta-cyclodextrin-thiol complexes to conjugated alkenes in water.

An environmentally benign and highly efficient supramolecular Michael addition of thiols from the secondary side of beta-cyclodextrin to alpha,beta-unsaturated compounds at the primary side in water is described in quantitative yields; products of undesirable side reactions resulting from polymerization are not observed; the use of cyclodextrin precludes the use of either acid or base and the catalyst can be recovered and reused.