ARENE ACTIVATION BY TRANSITION METALS

点击翻译按钮获取中文摘要

The broad, long-term aims of this proposal are to develop applications of arene-metal pi complexes to the total synthesis of challenging molecular arrays that are components of important natural product molecules, and to develop new methodology for asymmetric synthesis based on chiral auxiliary-directed nucleophile additions to arene-metal complexes. Investigations will be continued that are directed toward applications of arene-manganese tricarbonyl and arene(cyclopentadienyl) ruthenium cations in the synthesis of ristocetin A, a complex glycopeptide that is related to vancomycin and teicoplanin, the molecular structures of which present a challenging opportunity for the development of new and unique methodology for the construction of diaryl ethers having sensitive attached amino acid and peptide functionality. Synthetic approaches to these compounds, and their structural analogs, have become increasingly important as a result of the emergence of vancomycin-resistant strains of infectious bacteria during the past decade. Chiral auxiliary-directed asymmetric additions of carbon nucleophiles to donor-substituted arene-metal complexes provides a unique and potentially efficient method for the conversion of readily available aromatic molecules into optically pure cyclohexenones, themselves important building blocks for the synthesis of medicinally important terpenoids and steroids. This application proposes a continuing exploration of an approach developed in the P.I.'s laboratory, based on the chemistry of arene-manganese and arene-chromium complexes, which has resulted in unprecedented and unexpected diastereoselectivities.