Rhodium-Catalyzed Borylation of Aryl 2-Pyridyl Ethers through Cleavage of the Carbon–Oxygen Bond: Borylative Removal of the Directing Group
作者:Hirotaka Kinuta、Mamoru Tobisu、Naoto Chatani
DOI:10.1021/ja511622e
日期:2015.2.4
diboron reagent results in the formation of arylboronic acid derivatives via activation of the C(aryl)-O bonds. The straightforward synthesis of 1,2-disubstituted arenes was enabled through catalytic ortho C-H bond functionalization directed by the 2-pyridyloxy group followed by substitution of this group with a boryl group. Several control experiments revealed that the presence of a sp(2) nitrogen
Because diarylethers are present as an important motif in pharmaceuticals and natural products, extensive studies for the development of novel methods have been conducted. A conventional method for the construction of the diarylether moiety is the intermolecular cross-coupling reaction of aryl halides and phenols with a copper or palladium catalyst. We developed a catalytic decarbonylative etherification
Ruthenium(II) oxidase catalysis by direct dioxygen‐coupled turnover enabled step‐economical oxidative CH alkenylation reactions at ambient pressure. Versatile ruthenium(II) biscarboxylate catalysts displayed ample substrate scope and proved applicable to weaklycoordinating and removable directing groups. The twofold CH functionalization strategy was characterized by exceedingly mild reaction conditions
The nickel‐catalyzed borylation of aryl2‐pyridyl ethers via the loss of a 2‐pyridyloxy group is described. This method allows a 2‐pyridyloxy group to be used as a convertible directing group in C−H bond functionalization reactions. The nickel catalyst can also borylate arylmethyl 2‐pyridyl ethers, in which the stereochemistry at the benzylic position is retained in the case of chiral secondary benzylic
Intermolecular CH acyloxylations of phenols with removable directing groups were accomplished with a versatile rutheniumcatalyst. Specifically, a cationicruthenium(II) complex, formed in situ, enabled the chemoselective CH oxygenations of a broad range of substrates. The catalyst proved tolerant of synthetically valuable functional groups, and the substrate scope included both (hetero)aromatic