New Methods for Green Organic Synthesis

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Our proposal focuses on the development of iron and bismuth-derived Lewis acids as green catalysts. Their use in synthetic chemistry needs to be further developed because they are environmentally benign, relatively nontoxic and economic in comparison to other metals. The objective of our research is the development of new synthetic methods, with emphasis on catalytic and enantioselective procedures for the straightforward preparation of molecules of pharmaceutical interest. Catalytic asymmetric processes are indispensable for producing enantiomerically enriched compounds in modern organic synthesis, providing more economical and environmentally benign processes than methods requiring stoichiometric amounts of chiral reagents. Our results will lead to new tools for the preparation of molecules of biological interest. These studies will contribute to the development of new green synthetic methods using environmentally friendly and more economical Lewis acid catalysts.******A first part of our proposal deals with the development of new chiral iron complexes for the enantioselective insertion reaction of diazo compounds into the SiH bond of silanes and the CH bond. Firstly, an enantioselective insertion reaction will be developed using Fe salts with C2-symmetric chiral ligands. Consequently, the enantioselective insertion reaction of Fe carbenoid vinyl intermediates into the SiH bond will be studied. The enantioselective synthesis of chiral allyl silanes is indeed of prime importance. The subsequent allylation reaction of carbonyl compounds using the synthesized enantio-enriched allyl silanes will be undertaken. Secondly, silanes will be used in the enantioselective hydrosilylation reaction of ketones catalyzed by iron salts and the above-selected chiral ligands. Various silanes will be employed in combination with a wide selection of Fe salts and chiral ligands. New chiral iron N-heterocyclic carbene (NHC) catalysts will be prepared and evaluated.******A second part of our proposal will focus towards the development of an efficient catalytic system for the epoxidation and dihydroxylation of alkenes. A bioinspired non-heme iron complex capable of efficient oxidation of alkenes will be developed. Initial evidence showed that the previously prepared FeIIBolm's ligand complexes would have the appropriate geometry and electronics to work as oxidation catalysts. The asymmetric oxidation of sulfides using various iron chiral complexes will be studied as well.******A third part of our research program will be devoted to the use of Bi-derived Lewis acids. These Bi complexes will be first used as catalysts for the enantioselective crotylation reaction. BiIII-derived heterobimetallic complexes will be prepared and used as catalysts for selected enantioselective reactions.