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A Systems Approach to a One‐Pot Electrochemical Wittig Olefination Avoiding the Use of Chemical Reductant or Sacrificial Electrode
Author(s) -
Chakraborty Biswarup,
Kostenko Arseni,
Menezes Prashanth W.,
Driess Matthias
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202001654
Subject(s) - wittig reaction , electrochemistry , electrode , combinatorial chemistry , materials science , chemistry , organic chemistry
An unprecedented one‐pot fully electrochemically driven Wittig olefination reaction system without employing a chemical reductant or sacrificial electrode material to regenerate triphenylphosphine (TPP) from triphenylphosphine oxide (TPPO) and base‐free in situ formation of Wittig ylides, is reported. Starting from TPPO, the initial step of the phosphoryl P=O bond activation proceeds through alkylation with RX (R=Me, Et; X=OSO 2 CF 3 (OTf)), affording the corresponding [Ph 3 POR] + X − salts which undergo efficient electroreduction to TPP in the presence of a substoichiometric amount of the Sc(OTf) 3 Lewis acid on a Ag‐electrode. Subsequent alkylation of TPP affords Ph 3 PR + which enables a facile and efficient electrochemical in situ formation of the corresponding Wittig ylide under base‐free condition and their direct use for the olefination of various carbonyl compounds. The mechanism and, in particular, the intriguing role of Sc 3+ as mediator in the TPPO electroreduction been uncovered by density functional theory calculations.