Electrosynthesis of Unsymmetrical Polyaryls by a SRN1-Type Reaction
摘要:
Unsymmetrical polyaryls are electrosynthesized in liquid ammonia by a single-step S(RN)1 reaction in the presence of a redox mediator starting from aromatic halides and 2,6-di-tert-butyl phenoxide. With monoaryl halides activated by electron-withdrawing substituents (N of pyridyl or quinolyl, trifluoromethyl, cyano, sulfone, ester, ketone, alkyl sulfide, N+ of anilinium), biaryls are obtained in good yields (between 50 and 95%). The yields of ter- and quateraryls are lower (40% maximum). The reaction is extended to other ortho-disubstituted phenols. Elimination reactions of the tert-butyl groups from the products are achieved by a Friedel-Crafts reaction using either trifluoromethanesulfonic acid or aluminum trichloride as catalysts.
hindered phenol, 2,6-di-tert-butylphenol, efficiently reacts with various bromobenzenes in the presence of a palladium catalyst and a base to selectively afford the corresponding 1,1′-biphenyl-4-ol derivatives.
Aryloxide ions (Ar'O-) behave as C-nucleophiles towards diazosulfides (ArN=NSR; R = Ph, But) leading to unsymmetrical hydroxybiaryls (ArAr'OH) via C-C coupling. The reaction is particularly suited for the synthesis of terms which contain electron-withdrawing groups on the Ar moiety. The SRN1 mechanism is proposed on the grounds of experimental evidences.
Synthesis of fluorinated biaryl derivatives via SRN1 reactions
作者:René Beugelmans、Jacqueline Chastanet
DOI:10.1016/0040-4039(91)80813-l
日期:1991.7
Flourinated biaryl derivatives Y-C6-H4-ArOH (Y = F, CF3, OCF3) are obtained by coupling Y-C6-H4-Br(p) with anions derived from ArOH via a photostimulated SRN1reaction.
A selective synthesis of unsymmetrically substituted electron donor/electron acceptor biaryls is described which is based on an electrochemically or photochemically induced SRN1 reaction; the optical hyperpolarizability coefficients β are determined in solution for the various reaction products and found to be of the same order of magnitude as that of 4-nitro-aniline.
Phenoxide and naphthoxide ions as nucleophiles for SRN1 reactions: Synthesis of biphenyl and phenylnaphthyl derivatives
作者:René Beugelmans、Michèle Bois-Choussy
DOI:10.1016/s0040-4039(00)80279-8
日期:1988.1
Biphenyl or phenylnaphthyl derivatives are obtained by photostimulated SRN1reactions between the anion of phenols or naphthols and variously substituted haloarenes.