Non-Covalent Immobilization Methods for Homogeneous Organic Catalysts

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Catalytic reactions provide green, efficient, and selective syntheses of organic compounds when compared to waste-generating stoichiometric methods. However, many catalytic transformations are homogeneous and transition metal based. Metal impurities often remain in the desired compound after isolation and purification. Although selective homogeneous organocatalysts can be used, their activities and stabilities are often low, and their handling too demanding for economically viable industrial applications. The application and design of highly active heterogeneous organic catalysts has broad impacts in fine chemical and active pharmaceutical synthesis, yet to-date very few have made it to industrial practice due to limited reactivity and scope. Over the next five years the MacQuarrie group will implement an innovative method of supporting an array of chiral organic catalysts with enhanced homogeneous properties via charge matching between the ionically bound catalyst and the charged supports. The catalyst will not be rigidly bound to the surface enhancing reactivity and availability to reagents and stereocontrol will be improved over homogeneous analogues do to the confined environments the catalysts are placed in. The materials will be prepared in as inexpensive and green a manner as possible and the supports will range from highly ordered silicas to renewable resources such as biochar. Herein, we will take advantage of the charged nature of biochar (through its retained oxygen based functional groups) to enable facile heterogenization of several classes of organocatalysts. The proposed research program will be completed primarily with BSc students, however graduate students are included via adjunct status, to diversify the group and promote BSc students to consider graduate school. All students are trained for independent operation of on-site equipment, and senior BSc students, technicians, and postdoctoral researchers are paired with the BSc students on the projects, providing laboratory supervision. MacQuarrie has a well-established industrial collaboration with BioEnergy Inc. and the Lousibourg Seafoods Inc., both of which have provided in-kind funding for a postdoctoral researcher which is of paramount importance, providing consistency in research and facilitating student supervision, but their projects are fairly limited to industrially relevant work.