New Methods for Green Organic Synthesis

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Our proposal focuses on the development of bismuth(III)-derived and iron(II)-derived Lewis acids for environmentally benign chemical synthesis. Various Lewis acids will be developed as green catalysts for selected enantioselective reactions. The first objective of this proposal is to develop new chiral Bi(III)-derived catalysts enabling efficient asymmetric synthesis for reactions, such as the Mukaiyama aldol and the allylation reactions. Bi salts conjointly used with selected chiral ligands will be studied for the allylation and the crotylation of aldehydes. The ultimate goal will be to develop catalysts that will enable these processes to be performed in aqueous media. As a second part of our program involving Bi-derived catalysis, we plan the development of heterobimetallic complexes. The epoxide opening, the Henry and the Strecker reactions will be selected to evaluate the activity of the bifunctional catalysts. We also wish to explore new fields with our Fe(II)-derived asymmetric catalysts previously described for the asymmetric Mukaiyama aldol reaction in aqueous media. The reaction of dienol silyl enolates with carbonyl compounds will be further studied using Fe(II) salts and C2-symmetry ligands. Silyl dienol ethers will be tested with such chiral catalysts. A few natural targets will be selected to highlight the generality and versatility of our method. Finally, the Fe(II)-derived chiral complexes will be studied as oxidation catalysts. The development of Fe-catalyzed asymmetric epoxidation should lead to many advantages, as Fe is the most abundant transition metal on the earth and is relatively nontoxic. First, our proposal will include the use of such Fe complexes as active catalysts for alkene epoxidation and dihydroxylation using hydrogen peroxide as the terminal oxidant. Secondly, the chiral Fe complexes will be studied in the epoxidation of enones. The objective of our proposal is the development of new synthetic methods, with emphasis on catalytic and enantioselective procedures for the simple preparation of biologically and commercially important molecules. Our studies will contribute to the development of innovative green synthetic methods using new chiral Lewis acid catalysts.