RUI: Synthesis of Heterohelicenes Using Acetylene-Activated SNAr Reactions

Colby College, Waterville ME

Investigators

Abstract

The Chemical Synthesis Program of the Chemistry Division supports this project by Professor Jeffrey Katz, a faculty member in the Department of Chemistry at Colby College. He is investigating chemical methods that allow for the synthesis of chemical compounds called helicenes. Helicenes are unusual molecules that possess a rigid helical (screw-like) shape. The primary goal of the funded research is the development of technology that allows access to previously unknown helicenes containing nitrogen, oxygen, sulfur, and selenium atoms on terminal positions of the molecules. Compounds of this type have potential applications as chemical sensors, organic electronics, and new polymeric materials. Students working on this project are obtaining experience in organic chemical synthesis and materials chemistry. Professor Katz is highly active in the recruitment and retention of underrepresented minority students into chemistry and other scientific fields. He serves as co-Director of the Colby Achievement Program in the Sciences (CAPS), a summer bridge program at Colby College for entering first-year students from underrepresented backgrounds that fosters a climate of success and leadership within the minority student science population. Helicenes and their heteroaromatic variants are a promising compound class for use as chiral ligands, supramolecular building blocks, polymerization monomers, liquid crystals, optoelectronic materials, and components of molecular machines. A wide variety of [n]heterohelicenes are being accessed using acetylene-activated SNAr/anionic cyclization chemistry as the key diversifying transformation, a reaction cascade recently developed in the Katz laboratory. The cascade approach is efficient, highly modular, and allows for structural diversification at the final stages of the synthetic sequence. Further, the investigations target the production of non-racemic heterohelicenes through the use of chiral nucleophiles in the SNAr step of the cascade sequence, as well as adaptation of the method to produce heteroarene-terminated phenacenes. Undergraduate students working with Professor Katz travel to scientific conferences to present their research. Professor Katz leverages his attendance at these meetings by organizing and moderating Undergraduate Context Sessions, which support the educational environment for all attending undergraduate students. Such Sessions are included in the general programs of several major conferences in organic chemistry and have helped undergraduate students to become an increasingly recognized focus of the program structures.