COPPER AND NICKEL CATALYZED REACTIONS IN CHAN-LAM COUPLING, ISOUREA FORMATION, AND POLYOLEFIN UPCYCLING

Part 1. Chan-Lam couplings are a powerful tool in organic synthesis for C-N cross coupling. However, a major drawback to these chemistries is a need for an external oxidant which may be incompatible with substrates including proteins. Dehydrogenative couplings of NH-sulfoximines and sulfimines that do not require a terminal oxidant were reported by the Prof. Tiezheng Jia. DFT calculations were undertaken to give insight into the formation of hydrogen in these couplings. Calculations were also undertaken to understand the possible active catalysts in the system and probe the reaction pathways.Part 2. The use of N,N′-diisopropylcarbamimidate to prepare a tert-butyl ester of a carboxylic acid was required for the synthesis of a key pharmaceutical intermediate; however, commercial sources were not adequate to supply this reagent in the quantity and quality required for the campaign. An aerobic copper-catalyzed reaction between tert-butyl alcohol and N,N′-diisopropylcarbodiimide (DIC)was discovered to afford superior reaction rates and conversion. Screening and mechanistic studies concluded that CuICl is oxidized in situ by atmospheric O2 to a generate a more active CuII(OH)Cl species. The consumption of O2 over the course of the reaction resulted in the low-level production of impurities, but sufficient reaction rates and conversion of DIC were not attainable in the absence of O2. The production of the carbamimidate was safely executed using commercially available atmospheres of 4–5% O2/95–96% N2. Part 3. Plastics are inseparable from modern life as their properties mitigate some of the world’s most pressing challenges including reduction of food spoilage and energy consumption as well as preventing the spread of disease. However, their production, particularly of polyolefins, consumes energy and non-renewable resources. After use, they are rarely recycled and often their final destination is the landfill. A solution to the waste polyolefin is to “upcycle” to a value-added commodity polymer such as ethylene/acrylic acid copolymer. This work upcycles polyolefins by using copper and nickel catalysts to add CO and CO2 to the carbon backbone. Initially, conditions with small alkanes were screened. These conditions were then modified to functionalize model polyolefins. The addition of CO was applied to waste plastics.