Pd(Quinox)-Catalyzed Allylic Relay Suzuki Reactions of Secondary Homostyrenyl Tosylates via Alkene-Assisted Oxidative Addition.
نویسندگان
چکیده
Pd-catalyzed allylic relay Suzuki cross-coupling reactions of secondary alkyl tosylates, featuring a sterically-hindered oxidative addition and precise control of β-hydride elimination, are reported. The identification of a linear free energy relationship between the relative rates of substrate consumption and the electronic nature of the substrate alkene suggests that the oxidative addition requires direct alkene involvement. A study of the effect of chain length on the reaction outcome supports a chelation-controlled oxidative addition.
منابع مشابه
Allylic sp3 C-H borylation of alkenes via allyl-Pd intermediates: an efficient route to allylboronates.
Palladium catalyzed allylic C-H functionalization was performed using exocyclic alkene substrates. Multi-component synthesis of stereodefined homoallylic alcohols could be performed using a reaction sequence involving allylic C-H borylation and allylation of aldehydes.
متن کاملReversible alkene insertion into the Pd-N bond of Pd(II)-sulfonamidates and implications for catalytic amidation reactions.
Alkene insertion into Pd-N bonds is a key step in Pd-catalyzed oxidative amidation of alkenes. A series of well-defined Pd(II)-sulfonamidate complexes have been prepared and shown to react via insertion of a tethered alkene. The Pd-amidate and resulting Pd-alkyl species have been crystallographically characterized. The alkene insertion reaction is found to be reversible, but complete conversion...
متن کاملModular Synthesis of 1,2-Diamine Derivatives via Palladium-Catalyzed Aerobic Oxidative Cyclization of Allylic Sulfamides.
Allylic sulfamides undergo efficient aerobic oxidative cyclization at room temperature, mediated by a new Pd catalyst system consisting of 5% Pd(TFA)(2)/10% DMSO in THF. The synthetic utility of these reactions is enhanced by several features: (1) the sulfamide substrates are accessible in multi-gram scale from the corresponding allylic and primary amines, (2) the cyclic sulfamide products are ...
متن کاملPalladium-catalyzed enantioselective Heck alkenylation of trisubstituted allylic alkenols: a redox-relay strategy to construct vicinal stereocenters
In a Heck reaction using multi-substituted alkenes, the initial syn-carbopalladation sets two vicinal stereocenters by virtue of the migratory insertion process. Unfortunately, the resultant Pd–alkyl undergoes facile b-hydride elimination, which generally eliminates the stereochemistry imparted by migratory insertion. Recently, we have reported a modern variant of the Heck reaction, wherein the...
متن کاملMechanistic studies of Wacker-type intramolecular aerobic oxidative amination of alkenes catalyzed by Pd(OAc)2/pyridine.
Wacker-type oxidative cyclization reactions have been the subject of extensive research for several decades, but few systematic mechanistic studies of these reactions have been reported. The present study features experimental and DFT computational studies of Pd(OAc)(2)/pyridine-catalyzed intramolecular aerobic oxidative amination of alkenes. The data support a stepwise catalytic mechanism that...
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:
- Chemical science
دوره 5 6 شماره
صفحات -
تاریخ انتشار 2014