Asymmetric Epoxidation, Michael Addition, and Triple Cascade Reaction Using Polymer-Supported Prolinol-Based Auxiliaries.

Abstract The applicability of polymer-supported diphenylprolinol derivatives in directing either asymmetric epoxidation or Michael addition of suitable α,β-unsaturated substrates has been assessed. Epoxidation of cinnamaldehyde in the solid state give poorer yields and stereoselectivities than in the solution-phase systems. In contrast Michael additions of several aldehyde enolates to 2-nitro-1-arylalkenes gave results that approached or surpassed those in solution, and could be extended successfully to a three-component Michael/Michael/aldol cascade process. Comparisons of the results of pendant- versus crosslinked functionalized resins in these applications were revealing of the benefits and limitations of each, as were attempts to reuse the polymer-bound auxiliaries.