Cross‐Coupling of Organolithium with Ethers or Aryl Ammonium Salts by C−O or C−N Bond Cleavage

Abstract

Various aryl-, alkenyl-, and/or alkyllithium species reacted smoothly with aryl and/or benzyl ethers with cleavage of the inert C-O bond to afford cross-coupled products, catalyzed by commercially available [Ni(cod) ] (cod=1,5-cyclooctadiene) catalysts with N-heterocyclic carbene (NHC) ligands. Furthermore, the coupling reaction between the aryllithium compounds and aryl ammonium salts proceeded under mild conditions with C-N bond cleavage in the presence of a [Pd(PPh ) Cl ] catalyst. These methods enable selective sequential functionalizations of arenes having both C-N and C-O bonds in one pot.

Ethereal C–O Bond Cleavage Mediated by Ni(0)-Ate Complex: A DFT Study

“…However, this breakthrough was overlooked for decades, until quite recently. After the development of improved conditions, ArOR can now be used as a coupling partner in several types of transition metal (TM)-catalyzed cross-couplings and related transformations, such as Suzuki-Miyaura-type (B), [24][25][26][27][28][29][30][31] Negishi-type (Zn or Al), [32][33][34][35][36] Murahashi-type (Li), [37][38][39][40] and other reactions. [41][42][43][44][45][46][47][48][49][50] As a continuation of our work in this area, we reported in 2012 the first ethereal Negishi-type coupling of aryl alkyl ether 36) (Chart 1(1)) and in 2016 we reported a systematic examination of ethereal Murahashi-type reaction 37) (Chart 1(2)).…”

Organozinc‐Mediated Direct C−C Bond Formation via C−N Bond Cleavage of Ammonium Salts

“…Since the pioneering work by Wenkert et al. in 1988, several protocols for Ni or Pd‐catalyzed cross‐coupling reactions of ammonium salts via C−N bond cleavage have been reported . We recently reported Stille (Sn) and Murahashi (Li) couplings via C−N bond cleavage.…”

“…Sincet he pioneering work by Wenkert et al in 1988, [10a] several protocols for Ni or Pd-catalyzed cross-coupling reactions of ammonium salts via CÀNb ond cleavage have been reported. [10][11][12][13][14][15][16] We recently reported Stille (Sn) [13] and Murahashi (Li) [14] couplings via CÀN bond cleavage. Wes ubsequently found that aryl aluminum reagents could react efficientlywith aryl ammoniums in the presence of aN ic atalyst.…”

“…[12a] We tested these conditions, but no improvement was observed( entries 6-8), indicating that the reactivities of organozinc specieso fA rZnX and Ar 2 Zn wereq uite different. Finally, the amounts of 2a and LiCl, as well as the temperature, were optimized (entries [10][11][12][13][14]. Note that the reaction outcomed id not change much when less ZnPh 2 (1.5 or 1.0 equiv) was used, while the yield dropped to approximately 80 %w hen the reac-tion was performed at 60 8C( entry 12), or when 0.7 equiv of ZnPh 2 were used at 80 8C( entry 14).…”

Transition‐Metal‐Free Reaction of Aryltrimethylammonium Iodides with Arylzinc Reagents

“…A tactic is to convert arylamines to triazenes or arylammonium salts to weaken the C−N bonds before cleavage. We and other groups have performed some transition‐metal catalyzed cross‐coupling reactions using aryltrimethylammonium salts as the electrophilic partners in the past few years –…”