Biphasic hydroformylation, Wacker oxidation and hydrocarboxylation of water insoluble olefins have been investigated in the presence of chemically modified beta-cyclodextrins. In all cases, cyclodextrins appear more efficient than common mass transfer promoters to increase the activity and the selectivity of reactions. Most of the results are interpreted from the molecular recognition between the host cavity of modified cyclodextrins and substrate. The stability of the chemically modified cyclodextrins is also reported.