Development and Application of New Asymmetric Cycloaddition Reactions

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The investigation of a new approach to the synthesis of highly substituted dihydrobenzofurans, dihydroindoles, bicyclo{3.2.1}octenones and cyclobutanes will be made utilizing novel regio- and stereoselective Lewis acid catalyzed formal cycloaddition reactions of alkenes and alkynes with 1,4-benzoquinones, 1,4-benzoquinonediimides and alkoxy-alpha, beta-unsaturated enones. The exploration and development of enantiospecific variants of these new methods utilizing chiral Ti(IV) catalysts is planned and many provide the products in high enantiomeric purity. The structures of the products form all, or part of, the basic framework of many classes of biologically active molecules and chiral cyclobutanes may also be useful in the preparation of novel rod shaped polymers with interesting properties Specific targets include kadsurenone, a specific platelet-activating factor receptor antagonist, recaglamide, an antileukemic agent, viniferin, an antifungal agent, guianin, a representative neolignan, and acanthodoral, a structurally interesting natural product. In addition, syntheses of several 2-and 3-aryl-2,3-dihydrobenzofurans and their nitrogen analogs, i.e. 2-and 3-aryl-2,3-dihydroindoles, are planned. %%% With this award, the Organic Synthesis Program will support the research of Dr. Thomas A. Engler at the University of Kansas. The studies will explore new routes to asymmetric molecules based on new methods utililzing chiral Ti(IV) based reagents. The new synthetic methodology should benefit research in biochemistry and medicine, as well as in the chemical industry.