Professor Ken Houk visited Peking University in February 2024 to deliver the prestigious PKU Overseas Distinguished Guest Lectures.
The lectures were hosted by Zhi-Xiang Yu, the Changjiang Professor in the College of Chemistry and Molecular Engineering (CCME) of Peking University, and postdoc with Houk at UCLA 20 years ago.
“Professor Houk’s three lectures were rich, inspiring, and educational, with many new advances and knowledge in theoretical organic chemistry, computational chemistry, and enzyme catalysism,” said Prof. Yu. “At the end of each lecture, many professors and students had in-depth discussions with Professor Houk on issues related to his research and the frontiers of current organic chemistry and biochemistry.”
Houk is a member of the US National Academy of Sciences and a foreign member of the Chinese Academy of Sciences. He is an authority, pioneer, and trailblazer in theoretical and computational organic chemistry. His group is involved in developing rules to understand reactivity, computer modeling of complex organic reactions, and experimental tests of theoretical predictions. Houk collaborates widely with chemists worldwide, especially in China.
Pengchen Ma, Zhixiang Yu, Dong Meng, Guochao Xu, and Xiangyang Chen.
In his first lecture on February 19, entitled “Pericyclic Reactions and Ambimodal Transition States”, Houk introduced the concepts of ambimodal transition states and entropic intermediates and discussed higher order cycloadditions involving post transition-state bifurcations, such as the [6 + 4]/[4 + 6] reaction in the cycloheptatriene dimerization, [6 + 4]/[4 + 2] reaction in the streptoseomycin biosynthesis. In the second part of his talk, Houk discussed why and how some reactions violate Woodward-Hoffmann’s rules of pericyclic reactions, and predicted computationally several new polyene electrocyclic reactions of this type.
In his second lecture on February 21, entitled, ” Pericyclases – Enzymes that Catalyze Pericyclic Reactions”, Houk firstly introduced Diels–Alderases that catalyzes the famous Diels-Alder reaction. He then talked about his collaborations with his UCLA colleague, Yi Tang. He showed catalytic mechanisms of Diels-Alderases and other pericyclases, understood through the experimental or predicted structures of these enzymes and molecular dynamics simulations.
The third lecture, titled “Understanding and Predicting Reactivity and Selectivity: Hydrogen Atom Transfer and Aromatic Substitutions,” took place on February 23 as part of the Xinda Lecture series at the College of Chemistry and Molecular Engineering (CCME) at PKU. Houk presented his group’s research on understanding and predicting reactivity through quantum chemistry calculations and machine learning. He reviewed various theoretical reactivity models in the first part, including linear free energy relations and frontier orbital theory. The second part focused on the ZHAP (Zhou-Houk Aromatic Prediction) program, based on the FMO theory, which rapidly predicts regioselectivity in aromatic substitutions. Finally, he introduced HATpredict, a powerful machine learning program for predicting rates of hydrogen atom transfer reactions developed with UCLA PhD Xin Hong, now Professor at Zhejiang University.
Article and images by Professor Ken Houk.
