NEW DEVELOPMENTS IN ORGANOCOPPER CHEMISTRY

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The specific aim of the proposed work is to develop the chemistry of alpha-aminoalkylcopper reagents; a type of organocopper reagent that permits functionalization alpha to an amino group using the reactions characteristic of organocopper reagents. The specific objectives are to (1) expand the range of cuprate-electrophile reaction partners, (2) explore the reactivity and thermal stability of these reagents, and the configurational stability of cuprates with a C-Cu stereogenic center, (3) optimize reaction conditions, substrates, and reagents for effecting relative (diastereoselectivity) and absolute (enantioselectivity) asymmetric induction in the characteristic reactions of alpha-aminoalkylcuprates, and (4) develop the synthetic utility of these reagents by developing synthetic strategies for the synthesis of highly substituted 5-membered heterocyclic compounds with a focus on the pyrrolidine aza sugars. The synthetic approach to highly substituted pyrrolines, pyrrolidines, and pyrrolidinones involves the reaction of alpha-aminoalkylcuprates with scalemic propargyl substrates in a controlled anti-SN2' process followed by cyclization of the carbamate nitrogen or free amine onto the resultant allene. The work will extend the scope and synthetic utility of these organocopper reagents. Successful development of alpha-aminoalkylcuprate chemistry will contribute significantly to the synthesis of highly substituted pyrrolidines, piperidines, and their bicyclic analogs (i.e., pyrrolizidines, indolizidines, and quinolizidines). Complex alkaloids and simple nitrogen-containing compounds are biologically active agents representing important classes of antibacterial agents, CSN agents, and antiretroviral compounds. The polyhydroxy analogs (i.e., aza sugars) are an important class of glycosidase inhibitors and immunostimulators and are the focus of intense synthetic activity because of their effects upon glycoprotein processing enzymes. Inhibition of glycoprotein processing is potentially useful against illnesses such as cancers, malaria, diabetes, cystic fibrosis, bacterial, and viral infections including retro-viruses such as the human immunodeficiency virus (HIV). A need exists for a general synthetic approach to the aza sugars that is short, efficient, and which divergently leads to a large number of stereoisomers and analogues from a common intermediate. The proposed synthetic routes to pyrrolidine aza sugars will develop the potential synthetic power of alpha-aminoalkylcuprate chemistry.