Joslin Research Group
Sewanee: University of the South
Department of Chemistry
Project #1: Imine Synthesis using Transition Metals
Imines are of enormous importance because of their presence in natural products and their prominence in pharmaceuticals due to their anti-cancer and antifungal properties. Also, imines can be utilized as precursors in the synthesis of natural products through reactions such as aza-Diels-Alder to form tetrahydropyridines, reactions to form oxaziridines, and ene-reactions to form chiral amines. Imines are key starting materials and intermediates in many named organic reactions such as the Aza-Baylis-Hillman reaction, the Eschwiler-Clark reaction, and the Amadori rearrangement.
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Transition metals have been utilized in many areas of organic synthesis to facilitate difficult reactions and hence the field of organometallic chemistry has continued to grow. In most metal-nitrile adducts in the literature, the nitrile is coordinated to the metal center in an eta-1 fashion; however, there are some limited examples of eta-2 coordinated nitrile ligands through the pi-system. Eta-2-coordinated nitriles have been found to have unique reactivity towards electrophiles and nucleophiles and have allowed access to synthesis of imines through this rare coordination mode .
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We are interested in the synthesis of imines by reduction of nitriles via nucleophilic and electrophilic attack of eta-2-nitriles coordinated to tantalum and tungsten.
Project #2: Amide Synthesis using Transition Metals
Amides are the basic building blocks of many compounds that are vital to the pharmaceutical, peptide, and polymer industries. There is a rich history of synthesizing amides via the traditional coupling of carboxylic acids/acid chlorides with amines, but there are many drawbacks to this process. For instance, the need for activating agents, explosive additives, the generation of stoichiometric waste, and harsh reaction conditions, as well as problems with narrow substrate scope. We will develop a new methodology for synthesizing amides from amines and alcohols that addresses many of these drawbacks, with a specific focus on more atom-economical methods via the use of inexpensive and earth-abundant metals under mild conditions.
