Precise Introduction of the -CHnX3- n (X = F, Cl, Br, I) Moiety to Target Molecules by a Radical Strategy: A Theoretical and Experimental Study

J Am Chem Soc. 2021 Aug 25;143(33):13195-13204. doi: 10.1021/jacs.1c05208. Epub 2021 Aug 10.

Abstract

Addition of halomethyl radicals to form bioactive molecules has recently become an efficient strategy. The reaction has a bottleneck, however, which is the effective and selective generation of the proper halomethyl CHnX3-n radical by combining CHnX4-n with a carbon radical. Understanding the reactivity and selectivity of carbon radicals in the hydrogen atom transfer (HAT) and halogen atom transfer (XAT) reactions of CHnX4-n is key to the development of such an attractive method. With the help of the emerging data-driven strategy, DFT calculations were used to explore various correlations. For selectivity, the relative energy barriers between HAT and XAT reactions (ΔGH - ΔGX) correlate reasonably well with the three parameters ΔGH, ΔGX, and IP, and the correlation studies reveal that the calculated IPinver and the experimental ΔBDE can be used to conveniently predict the selectivity. Predicted selectivities are consistent with experimental determinations. This work not only provides a possibility for selecting carbon radicals with the known or easily obtained physicochemical data but also demonstrates that the informatic workflow such as generating data and identifying correlations has potential applications in mining reaction rules.

Publication types

  • Research Support, Non-U.S. Gov't