Metal-catalyzed activation of ethers via C–O bond cleavage: a new strategy for molecular diversity

Abstract

In 1979, the seminal work of Wenkert set the standards for the utilization of aryl and vinyl ethers as coupling partners via C-O bond-cleavage. Although the topic remained dormant for almost three decades, the last years have witnessed a renaissance in this area of expertise, experiencing an exponential growth and becoming a significant discipline within the cross-coupling arena. The means to utilize readily accessible aryl or vinyl ethers as counterparts does not only represent a practical, powerful and straightforward alternative to organic halides, but also constitutes an excellent opportunity to improve our chemical knowledge on a relative unexplored area of expertise. This review summarizes the most significant developments in the area of C-O bond-cleavage when employing aryl or vinyl ethers, providing a detailed overview of the current state of the art and including future aspects, when applicable.

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

“…Based on this work, together with our previous mechanistic study on etheric Kumada-Tamao reaction, we identify and characterize a novel catalytic cycle for cross-coupling mediated by Ni(0)-ate complex.Key words cross-coupling; ether; nickel catalyst; organolithium; organozinc; density functional theory (DFT) calculation Efficient and selective cleavage and transformation of C-O bonds, particularly by means of cross-coupling methods, has attracted great interest, since compounds containing C-O moieties occur widely in nature and are also extensively utilized in industry.1-8) Among C-O compounds, ethers are particularly attractive, [1][2][3][4][5][6][7][8] as they offer the advantages of 1) high atom economy/conversion efficiency (the use of ethers as simple as MeO as substrates affords fewer by-products compared with tosylate, mesylate, triflate, phosphate, etc. ), 2) environmental compatibility (cleavage of the C-O moiety in ether releases non-halogen-containing waste), and 3) excellent stability, easy accessibility and wide diversity.…”

“…1-8) Among C-O compounds, ethers are particularly attractive, [1][2][3][4][5][6][7][8] as they offer the advantages of 1) high atom economy/conversion efficiency (the use of ethers as simple as MeO as substrates affords fewer by-products compared with tosylate, mesylate, triflate, phosphate, etc. ), 2) environmental compatibility (cleavage of the C-O moiety in ether releases non-halogen-containing waste), and 3) excellent stability, easy accessibility and wide diversity.…”

Ipso-Borylation of Aryl Ethers via Ni-Catalyzed C–OMe Cleavage

“…3 If successful, such a strategy would not only open up new vistas in C-B bond-formation but also might represent a significant step-forward for implementing aryl methyl ethers as privileged counterparts in cross-coupling endeavours. 2 As part of our interest in C-O bond-functionalization, 13 we describe herein the first catalytic ipso-borylation of aryl methyl ethers via C(sp 2 )-and even C(sp 3 )-O cleavage, thus exploiting a previously unrecognized opportunity in this field. 14,15 This protocol is characterized by its wide scope under mild conditions and by an exquisite divergence in site-selectivity that can be modulated by a judicious choice of the corresponding boron reagent.…”

“…1,2 While the utilization of activated aryl esters, carbamates or sulfonates has become routine, it comes as a surprise that aryl methyl ethers, the simplest derivatives in the phenol series, have received much less attention. 2 This is likely due to the high activation energy required for C-OMe scission and the low propensity of methoxy residues to act as leaving groups. Not surprisingly, these reactions remain essentially confined to C-C bond-formations using highly reactive, well-defined, stoichiometric and, in many cases, air-sensitive organometallic reagents (Scheme 1, path a).…”

Handy Protocols using Vinyl Nosylates in Suzuki–Miyaura Cross‐Coupling Reactions

“…[8] In contrast, the electrophilic partners have been less investigated. Nevertheless,t he traditional use of halides hasb een expanded to the so-called pseudohalides [9] such as some ethers, [10] esters, [9a,b,d] carbamates, [9a,b,d] sulfamate, [9a,b] and of course sulfonates. In the latter family,t riflate derivatives [11] are now very popular but alternatives,s uch as mesylate, [12] tosylate, [13] nonaflate, [14] fluorobenzenesulfonate, [15] have also been exploreda nd some are currently under development.…”