40628-60-2Relevant academic research and scientific papers
Carbonylative Suzuki-Miyaura couplings of sterically hindered aryl halides: Synthesis of 2-aroylbenzoate derivatives
Bayer, Annette,Ismael, Aya,Skrydstrup, Troels
supporting information, p. 1754 - 1759 (2020/03/17)
We have developed a carbonylative approach to the synthesis of diversely substituted 2-aroylbenzoate esters featuring a new protocol for the carbonylative coupling of aryl bromides with boronic acids and a new strategy to favour carbonylative over non-carbonylative reactions. Two different synthetic pathways-(i) the alkoxycarbonylation of 2-bromo benzophenones and (ii) the carbonylative Suzuki-Miyaura coupling of 2-bromobenzoate esters-were evaluated. The latter approach provided a broader substrate tolerance, and thus was the preferred pathway. We observed that 2-substituted aryl bromides were challenging substrates for carbonylative chemistry favouring the non-carbonylative pathway. However, we found that carbonylative Suzuki-Miyaura couplings can be improved by slow addition of the boronic acid, suppressing the unwanted direct Suzuki coupling and, thus increasing the yield of the carbonylative reaction.
2-benzoylbenzoic acid: A photolabile mask for alcohols and thiols
Jones, Paul B.,Pollastri, Michael P.,Porter, Ned A.
, p. 9455 - 9461 (2007/10/03)
Photolysis of 2-benzoylbenzoate esters of primary and secondary alcohols 1 in the presence of a hydrogen donor (2-isopropanol) or an electron donor (primary amines) produces the corresponding alcohol in high yield. The fate of the benzoate is dependent on the conditions used for the photoreaction. In 2-propanol, the ketyl radical that derives from photoreduction dimerizes, to afford the benzpinacol product 3,3"-diphenylbiphthalidyl, 5. In the presence of amines the product is 3-phenylphthalide, 6, a benzhydrol derivative which is the result of simple reduction of the ketone followed by lactonization. While the photoproduct of the benzoate - 2-propanol reaction results from anticipated free radical chemistry, the amine-promoted reaction appears to result from a second, "dark", electron transfer process. We conclude that 2-benzoylbenzoic acid is an effective photolabile protecting group for primary and secondary alcohols, and preliminary studies indicate that thiols can be protected in an analogous way. Studies on the effect of benzophenone substituents and reaction solvent on the benzhydrol:benzpinacol product ratio provide mechanistic insight into the process.
