Harnessing the Power of Weak Bonds: Cleavage of N-O Bonds as Key Steps in Domino and Rearrangement Reactions of Functionalized Hydroxylamines

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With the support of the Chemical Synthesis (SYN) program in the Division of Chemistry, Professor László Kürti of Rice University is studying the design and development of new streamlined methods for the production of nitrogen-containing molecules. These new methods offer potentially greener and more economical alternatives for manufacturing intermediates and target molecules for numerous applications ranging from agriculture, medicine, molecular electronics all the way to 21st century materials. The new molecular transformations exploit weak nitrogen-oxygen (N–O) bonds, which when ruptured, initiate carefully orchestrated sequences of chemical reactions, also known as domino reactions. The domino processes cause the skeletons of the original molecules to rearrange into completely new ones. These types of molecular rearrangement reactions are among the most efficient and atom-economical processes known to chemistry. Prof. Kürti has been a faculty sponsor of the Rice University chapter of Fun with Chemistry, an outreach program that has the short-term goal of establishing a robust Houston-area satellite program. The long-term goal is to initiate similar satellite programs in other major Texas metropolitan areas. This outreach program provides K-12 students in Texas with the opportunity to participate in experimental-learning through captivating science experiments. Curiosity for science is piqued through fun demonstrations that highlight important educational lessons by utilizing a variety of role models. In particular, this educational program strives to reach traditionally underrepresented minorities and highlight that anyone can be a scientist! The ultimate goal of the program is to inspire young students to pursue careers in science, technology, engineering, and mathematics (STEM)-fields.Professor Kürti’s research group will be exploring four fundamentally new domino reaction strategies to produce small-ring- and aromatic heterocycles. The common theme of these transformations is the nature of the activation of the substrates or intermediates: by a scission of their weak N–O bonds. Depending on the strategy, this N–O bond cleavage either triggers or drives the particular transformation, which include new ring-contractions and [3,3]-sigmatropic rearrangements. Making highly-substituted nitrogen-containing molecules is a long-standing challenge in synthetic organic chemistry. The proposed project aims to address this challenge: the driving force offered by cleaving N–O bonds enables the operationally simple construction of numerous challenging nitrogen-containing molecules, including ones currently unknown to chemistry. The proposed research promises to offer new, reliable, transition metal-free synthetic methods as alternatives to traditional approaches, and is expected to have impact on chemists in academic, governmental and industrial laboratories.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.