Formation of ArF from LPdAr(F): catalytic conversion of aryl triflates to aryl fluorides.
نویسندگان
چکیده
Despite increasing pharmaceutical importance, fluorinated aromatic organic molecules remain difficult to synthesize. Present methods require either harsh reaction conditions or highly specialized reagents, making the preparation of complex fluoroarenes challenging. Thus, the development of general methods for their preparation that overcome the limitations of those techniques currently in use is of great interest. We have prepared [LPd(II)Ar(F)] complexes, where L is a biaryl monophosphine ligand and Ar is an aryl group, and identified conditions under which reductive elimination occurs to form an Ar-F bond. On the basis of these results, we have developed a catalytic process that converts aryl bromides and aryl triflates into the corresponding fluorinated arenes by using simple fluoride salts. We expect this method to allow the introduction of fluorine atoms into advanced, highly functionalized intermediates.
منابع مشابه
Evidence for in situ catalyst modification during the Pd-catalyzed conversion of aryl triflates to aryl fluorides.
A mechanistic investigation of the Pd-catalyzed conversion of aryl triflates to fluorides is presented. Studies reveal that C-F reductive elimination from a LPd(II)(aryl)F complex (L = t-BuBrettPhos or RockPhos) does not occur when the aryl group is electron rich. Evidence is presented that a modified phosphine, generated in situ, serves as the actual supporting ligand during catalysis with suc...
متن کاملA Fluorinated Ligand Enables Room-Temperature and Regioselective Pd-Catalyzed Fluorination of Aryl Triflates and Bromides
A new biaryl monophosphine ligand (AlPhos, L1) allows for the room-temperature Pd-catalyzed fluorination of a variety of activated (hetero)aryl triflates. Furthermore, aryl triflates and bromides that are prone to give mixtures of regioisomeric aryl fluorides with Pd-catalysis can now be converted to the desired aryl fluorides with high regioselectivity. Analysis of the solid-state structures o...
متن کاملStudying Regioisomer Formation in the Pd-Catalyzed Fluorination of Aryl Triflates by Deuterium Labeling
Isotopic labeling has been used to determine that a portion of the desired product in the Pd-catalyzed fluorination of electron-rich, non-ortho-substituted aryl triflates results from direct C-F cross-coupling. In some cases, formation of a Pd-aryne intermediate is responsible for producing undesired regioisomers. The generation of the Pd-aryne intermediate occurs primarily via ortho-deprotonat...
متن کاملEfficient synthesis of aryl fluorides.
Selective functionalization reactions of aromatic and heteroaromatic halides with carbon, oxygen, and nitrogen nucleophiles have attracted much attention in the last decades. In addition to typical metal-catalyzed coupling reactions, direct functionalization of aryl halides through the formation of Grignard reagents offer new ways for the efficient construction of biologically interesting carbo...
متن کاملPalladium-catalyzed conversion of aryl and vinyl triflates to bromides and chlorides.
The palladium-catalyzed conversion of aryl and vinyl triflates to aryl and vinyl halides (bromides and chlorides) has been developed using dialkylbiaryl phosphine ligands. A variety of aryl, heteroaryl, and vinyl halides can be prepared via this method in good to excellent yields.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Science
دوره 325 5948 شماره
صفحات -
تاریخ انتشار 2009