Solvent-Controlled Switchable Synthesis of gem-Difluoro Compounds from Anhydrides under Photoredox Catalysis

01 June 2022, Version 2
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

The outstanding impact of fluorine atom in drug discovery cannot be overestimated. Substantially, the incorporation of the gem-difluoro (CF2) group into organic frameworks is highly sought due to the influence of this unit on physicochemical and pharmacological properties of molecules. Yet, introduction of CF2 moiety into organic structures is a step-intensive preparation, and known approaches are often limited to certain classes of molecules. Development of strategies for a rapid incorporation of gem-difluoro synthon that utilizes inexpensive commercial reagents is highly desirable. In the context of divergency and applicability of such reagents, switchable synthesis can be beneficial to access a wide range of fluorinated compounds. Herein we report a mild and operationally simple protocols to access various gem-difluoro compounds that employs chlorodifloroacetic anhydride (CDFAA) as a low cost and versatile fluoroalkylating reagent. Detailed mechanistic investigations revealed that electron-transfer photocatalysis triggers mesolytic cleavage of a C−Cl bond generating a gem-difluoro carboxy radical. In the presence of alkene molecule, this radical species acts as an efficient and unique bifunctional reagent that, under solvent-controlled reaction conditions, delivers a wide range of gem-difluorinated γ-lactams, γ-lactones, as well as promotes oxy-perfluoroalkylation. These protocols are flow and batch scalable, possess excellent chemo- and regioselectivity, and can be used for the late-stage diversification of biorelevant molecules.

Keywords

photoredox
anhydrides
bifunctional reagent
divergent synthesis
gem-difluoro compounds
mechanisms
light-mediated

Supplementary materials

Title
Description
Actions
Title
Supplementary Infromation
Description
The document includes synthetic procedures, NMR spectra, characterization for all new compounds, and further details of computational studies.
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.