Electroreductive Defluorination of Trifluoromethyl Ketones and Trifluoroacetic Acid Derivatives

Abstract

Difluoroenol silyl ethers 5 and 6, difluoroketene silyl (O,O-, O,S-, and O,N-) acetals 9 and 21, and 2,2-difluoro-2-trimethylsilylacetates 10 were prepared by electroreductive defluorination of trifluoromethyl ketones and trifluoroacetic acid derivatives in an MeCN-TBAB-chlorotrialkylsilane system using a carbon rod as an anode and a lead plate as a cathode. TBAF- or KF-CuI-promoted alpha-alkylation of 10 with electrophiles such as aldehydes, ketones, imine, acylhalides, and alkylhalides provided alpha-alkylated-alpha,alpha-difluoroacetates in good to excellent yields.

AgI‐Promoted Difluoromethylation of Isocyanides To Give Difluoromethylated Phenanthridines

“…General Procedure for Synthesis of Substrates (Derivatives of Isocyanides): 2‐Bromoaniline (20 mmol), phenylboronic acid (24 mmol), K 2 CO 3 (2 m aq. ; 45 mL) and DME (40 mL) were added to an oven‐dried three‐necked flask under a gentle stream of nitrogen.…”

Recent advances in transition metal-catalyzed Csp2-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

“…Unlike previous protocols where an excess of copper is required, this approach presents some advantages such as: (i) stability and availability of the required 2-silyl-2,2-difluoroacetates from trifluoroacetates or chlorodifluoroacetates [58–60]; (ii) high functional group tolerance as the reactions proceed smoothly under mild conditions; and (iii) the reaction being catalytic in copper.…”

Functionalized fluoroalkyl and alkenyl silanes: Preparations, reactions, and synthetic applications

“…The acetamides 108 could transfer difluoro-(amidocarbonyl) moiety to formyl group of isobutenal on treating with potassium fluoride to give 109. The syntheses of a-substituted difluoroacetate 111 by the fluoride ion-catalyzed Si-C bond activation of 106 followed by difluoro(carbophenoxy)methyl group transfer to a variety of electrophiles are summarized in Scheme 27 [39]. The reaction with aromatic and a,b-unsaturated aldehydes, ketone, imine, acyl chloride and chloroformate gave the desired adducts in good to excellent yields.…”