Friday, May 27, 2022 - 12:00pm

Abstract: The world around us, from the medicines we take, to the food we eat, to the plants and animals surrounding us, is composed of carbon-carbon (C–C) bonds. In order to construct these C–C bonds, we rely on previously developed methodologies. In an ever growing world, the need for new technologies to tackle more challenging problems has grown significantly. Catalysis has emerged in the last century as a reliable, efficient and sustainable method to synthesize C-C bonds. In particular, first row transition-metal catalysis has stood out for its unique reactivity and interesting mechanistic pathways. Herein, four nickel-catalyzed transformations that provide highly complex carbon scaffolds will be discussed. In addition, key mechanistic features will be examined.

First, a nickel-catalyzed Kumada cross-coupling reaction of benzylic sulfonamides will be discussed. A significant by-product that was initially was observed was substituted styrenes resulting from β-hydride elimination. In order to address this problem, we synthesized highly branched substrates and this diminished the formation of the undesired by-product. In addition, the scope of the includes heterocycles and alternative Grignard reagents.

Next, cross-electrophile coupling reactions of benzylic, allylic and propargylic sulfonamides will be presented. These strategies allow for the synthesis of highly strained cyclopropanes in a diastereoselective manner. During the mechanistic investigation, we discovered that catalytic turnover was rate determining and we hypothesized that known elementary steps could be inserted to develop a domino reaction. To this end, we established a domino reaction of propargylic sulfonamides that involved discrete cross-electrophile coupling and dicarbofunctionalization to afford tetrasubstituted vinylcyclopropanes. Based on experimental and mechanistic experiments, we proposed a bifurcated mechanism that produces both diastereomers of product.

Finally, a conjunctive cross-electrophile coupling reaction involving mesylate electrophiles and an internal olefin will be discussed. This methodology builds on our laboratory’s previously developed cross-electrophile coupling reaction 1,3-dimesylates. The scope of the reaction contains electron-withdrawing and electron-donating functional groups. Additionally, we performed preliminary mechanistic experiments to demonstrate that the mechanism likely generates diiodides in-situ, initiates at the secondary center and proceeds through radical intermediates and.


Kirsten Anne Hewitt


Jarvo Group


NSII 1201