502159-05-9Relevant academic research and scientific papers
Continuous-flow synthesis of functionalized phenols by aerobic oxidation of grignard reagents
He, Zhi,Jamison, Timothy F.
supporting information, p. 3353 - 3357 (2014/04/03)
Phenols are important compounds in chemical industry. An economical and green approach to phenol preparation by the direct oxidation of aryl Grignard reagents using compressed air in continuous gas-liquid segmented flow systems is described. The process tolerates a broad range of functional groups, including oxidation-sensitive functionalities such as alkenes, amines, and thioethers. By integrating a benzyne-mediated in-line generation of arylmagnesium intermediates with the aerobic oxidation, a facile three-step, one-flow process, capable of preparing 2-functionalized phenols in a modular fashion, is established. Putting on airs: Aerobic oxidation of (hetero)aryl Grignard reagents using compressed air proceeds with a gas-liquid continuous-flow system, thus enabling preparation of fucntionalized phenols. By integrating an in-line generation of ArMgBr intermediates with the aerobic oxidation, ortho-functionalized phenols can be assembled. The method demonstrates good functional-group (FG) compatibility, mild reaction conditions, and short reaction times.
Identification of Suitable Ligands for a Transition Metal-Catalyzed Reaction: Screening of a Modular Ligand Library in the Enantioselective Hydroboration of Styrene
Blume, Florian,Zemolka, Saskia,Fey, Thorsten,Kranich, Remo,Schmalz, Hans-Guenther
, p. 868 - 883 (2007/10/03)
Based on a general modular synthetic scheme, a variety of chiral bidentate P/P-, P/S-, P/N-, and P/Se-ligands is accessible in an efficient divergent manner starting from phenol or naphthol derived backbone systems. A library of 20 selected ligands was tested in the Rh-catalyzed asymmetric hydroboration of styrene to give 1-phenylethanol in up to 91% ee after oxidative work-up. It was demonstrated that small variations of the ligand structures lead to pronounced, unpredictable differences in the performance of the in situ generated rhodium complexes. The modular approach should be applicable for the identification and optimization of suitable ligands for other transition metal-catalyzed transformations with comparably low effort.
