Progress in Chengdu Asymmetric Hydrofluorination of Olefins

[ Instrument Network Instrument R & D ] Fluorine compounds are widely used in medicine, pesticides, materials and other fields. Currently, more than 20% of drug molecules and more than 25% of pesticide molecules on the market contain at least one fluorine atom (including chiral fluorine). Hydrofluorination of olefins is one of the effective methods for the synthesis of fluorinated compounds. However, it is difficult to introduce chiral factors in the existing main technical approaches. How to achieve efficient asymmetric hydrofluorination of olefins has always been an important issue for chemists.

Fluorine compounds are harmful to the human body. A small amount of fluorine (within 150 mg) can cause a series of pain. A large amount of fluoride can cause acute poisoning when it enters the body. Depending on the amount of inhaled, various conditions can occur, such as anorexia, nausea, abdominal pain, stomach ulcers, cramps, bleeding and even death. If the amount of poisoning is insufficient to cause death, the human body can quickly recover from fluorosis. Especially when using intravenous or intramuscular calcium gluconate treatment, about 90% of the fluorine can be quickly eliminated, and the remaining fluorine needs time to remove. Frequent exposure to fluoride can easily cause bones to harden, become brittle, and teeth to become brittle and broken. Excessive fluoride in drinking water in some areas can easily lead to fluoride poisoning.

Liao Jian, a researcher at the Natural Products Research Center of the Chengdu Institute of Biology, the Chinese Academy of Sciences, has developed an effective catalytic system that achieves asymmetric hydrofluorination of aryl olefins, and synthesized a series of chiral benzyl fluoride compounds, including the later stages of achieving natural products Chiral fluorination modification; and the in-depth study of the reaction mechanism by low temperature nuclear magnetic resonance technology.

Nuclear magnetic resonance is a physical process in which atomic nuclei with non-zero magnetic moments undergo a Zeeman split in the spin energy level under the action of an external magnetic field, and absorb a certain frequency of radio frequency resonance. Nuclear magnetic resonance spectroscopy is a branch of spectroscopy, whose resonance frequency is in the radio frequency band, and the corresponding transition is the transition of nuclear spins at the nuclear Zeeman level.

MRI application: Magnetic resonance imaging (MRI) examination has become a common imaging examination method. As a new type of imaging examination technology, magnetic resonance imaging will not affect human health, but six types of people are not suitable for MRI. Examination: people with pacemakers, people with or suspected of metal foreign bodies in the eyeballs, people with silver aneurysm ligation, people with metal foreign bodies in their bodies or metal prostheses, critically ill patients at risk, Phobia patients, etc. Do not bring monitoring equipment, rescue equipment, etc. into the MRI room. In addition, pregnant women less than 3 months pregnant do not need to undergo MRI.

This research provides a solution to the long-standing key problems in the field of olefin hydrofluorination (the lack of an effective chiral catalytic system); it also provides technical support for the design and research of drugs, materials, and so on. The research results were published in ACS Catalysis in the form of a dissertation. The first author of the dissertation was PhD student Yin Xuemei. The research work was funded by the National Natural Science Foundation of China, the Strategic Biological Resources Project of the Chinese Academy of Sciences, and the Science and Technology Department of Sichuan Province.

Source: Encyclopedia, Chengdu Institute of Biology