Topic: Asymmetric Nucleophilic Fluorination Via H-Bond-Phase Transfer Catalyst

Speaker: Aria Vahdani - Michigan State University

Host: Professor Babak Borhan

Date: Wednesday, November 6, 2019

Time: 3:00 PM

Location: 136 CEM

More Information:

The unique chemical behavior of fluorine has eluded chemists for decades and resulted in the widespread development of modernized and improved methods for activating fluoride both as an electrophile and a nucleophile for use organic synthesis. However, due to the poor insolubility of abundant alkali metal fluoride salts in organic media, as well as the high reactivity of the unsolvated fluoride anion, the development of asymmetric methods utilizing nucleophilic fluoride has been lacking considerably. Comparatively, methods of electrophilic fluorination typically involve use of hazardous and costly reagents. More recently, methods have emerged which combine the hydrogen bonding capability of fluoride, with the poor solubility of alkali metal fluorides, as well as the employment of phase transfer catalysts in order to asymmetrically fluorinate C-F sp3 bonds, using an anionic source of fluoride. The key to this process, is the use of a chiral urea phase transfer catalyst, which hydrogen bonds to, and solubilizes fluoride as its anion. This is analogous to the only known enzyme in nature which catalyzes the formation of a C-F bond via H-bonding interactions.

References:

 

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