DFT studies on the mechanism of palladium-catalyzed carbon–silicon cleavage for the synthesis of benzosilole derivatives

Abstract

DFT calculations have been carried out to study the detailed mechanism of Pd-catalyzed intermolecular coupling reactions of 2-silylaryl bromides with alkynes via selective cleavage of C(sp(3))-Si bonds. Through our calculations, we found that, starting from the alkenylpalladium intermediate derived from oxidative addition of the substrate C-Br bond followed by alkyne insertion, there are two possible pathways leading to the formation of the benzosilole product. Furthermore, these two pathways were found to be competitive. In this paper, we will present the detailed mechanistic study and analyze the results we have obtained.

Regioselective Synthesis of Polycyclic and Heptagon‐embedded Aromatic Compounds through a Versatile π‐Extension of Aryl Halides

“…The rate‐determining step is the C−Br oxidative addition of 2‐bromobenzoate to Pd II ( C +cesium 2‐bromobenzoate→ D +Cs 2 CO 3 ) with a free‐energy barrier of 35.7 kcal mol −1 , which is moderately high and consistent with the harsh reaction condition at elevated temperature (130 °C) and long reaction time (18 h). The mechanism involves the association/dissociation of phosphine ligands and therefore, a higher concentration of phosphine is needed in order to facilitate the reaction . Species G is neither experimentally observed by GC analysis nor isolated.…”

“…[24] Species G is neither experimentally observed by GC analysis nor isolated. [24] Species G is neither experimentally observed by GC analysis nor isolated.…”

Mechanistic Insights into Palladium‐Catalyzed Silylation of Aryl Iodides with Hydrosilanes through a DFT Study

“…With new advances in theoretical methods and increased computational power, computational tools have become an important method for elucidating reaction mechanisms and the origin of various selectivities in transition‐metal‐catalyzed organic reactions . Although numerous computational studies about the mechanism of palladium‐catalyzed carbon–carbon cross‐coupling reactions, such as Suzuki–Miyaura coupling, Heck coupling, Sonogashira cross‐coupling, Stille coupling, and Hiyama coupling, have been reported, those about the palladium‐catalyzed silicon–carbon coupling reaction are still rare . To the best of our knowledge, no theoretical studies are available for the title reaction.…”

Mechanistic Investigation into RhIII‐Catalyzed Intramolecular Redox‐Neutral Annulation of Aryl Hydrazines with a Tethered Alkyne

“…This step is exergonic by 7.9 kcal mol −1 . Amide ligand in L‐91 is easily protonated through the incorporation of an HOAc molecule, which proceeds without an energy barrier to give intermediate L‐10 . Finally, the protonation of L‐10 easily produces the desired indole product P and regenerates the active catalyst K , the process of which is calculated to require a modest 4.0 kcal mol −1 ( L‐10 → L‐12 ).…”