Electrochemically Mediated Oxidation of Sensitive Propargylic Benzylic Alcohols

Abstract

The electrochemical oxidation of sensitive propargylic benzylic alcohols having varying substituents is reported. We describe the preparation and characterization of N-hydroxytetrafluorophthalimide (TFNHPI) and pseudo-high-throughput development of a green electrochemical oxidation protocol for sensitive propargylic benzylic alcohols that employs TFNHPI as a stable electrochemical mediator. The electrochemical oxidation of propargylic benzylic alcohols was leveraged to develop short synthetic pathways for preparing gram quantities of resveratrol natural products such as pauciflorols.

Radical reactions enabled by polyfluoroaryl fragments: photocatalysis and beyond

“…210,211 Nevertheless, using this reagent, propargyl alcohols 94.1 were electrochemically oxidized into ketones 94.2 (Scheme 94). 212 The library of analogues of classical NHPI reagents is very diverse. 211 Kanai group decided to replace one carbonyl in fluorinated N-hydroxyphthalimide with a C(sp 3 ) atom.…”

Electrochemically Enabled Total Syntheses of Natural Products

“…Indirect electrolysis is an indispensable technique for the manipulation of redox sensitive substrates, though it is seen infrequently in the arena of total synthesis. [119] During the course of an indirect electrolysis, an exogenous mediator with a different oxidation (or reduction) potential or a markedly different rate of redox chemistry than the substrate of interest is acted upon by the electrode. [120] This oxidized (or reduced) mediator species then acts upon the substrate to facilitate the desired transformation.…”

Selective Electrochemical Halogenation of Functionalized Quinolone

“…Analytical thin-layer chromatography was performed by using commercially prepared 100−400 mesh silica gel plates (GF 254 ), and visualization was effected at 254 nm. 1 H, 13 C, and 19 F NMR spectra were recorded using a Bruker DRX-400 spectrometer using CDCl 3 or (CD 3 ) 2 SO as the solvent. The chemical shifts of CDCl 3 are referenced to signals at 7.26 and 77.0 ppm, respectively.…”

“…Electrochemical is an ideal alternative to chemical oxidants, it can utilize electrons as traceless reagents, and is an organic synthetic technology for molecule construction by gaining and losing electrons. – Compared with traditional organic synthesis, electrochemical organic synthesis has several advantages such as (1) a more mild and eco-friendly synthesis strategy, – (2) a short reaction time, , and (3) the ease of scaling up the reaction . Electrochemical synthesis has received increasing attention from synthetic chemists in the past two decades. – In 2017, Baran surveyed the advances in synthetic organic electrochemistry since 2000 and the challenges ahead. Recently, a series of transition-metal-catalyzed and metal-free electrochemical organic synthesis reactions have been reported successfully by Lei’s, – Mei’s, – Ackermann’s, , and other groups.…”