Kadnikov, Dmitry V.; Larock, Richard C. published the artcile< Palladium-Catalyzed Carbonylative Annulation of Internal Alkynes: Synthesis of 3,4-Disubstituted Coumarins>, Computed Properties of 112-63-0, the main research area is coumarin preparation palladium carbonylative annulation internal alkyne; carbonylation annulation iodophenol alkyne benzopyranone preparation; acyl palladium carbonylation annulation iodophenol alkyne benzopyranone preparation; cyclization carbonylation alkyne benzopyranone preparation; insertion cyclization carbonylation alkyne benzopyranone preparation; iodobenzenemethanol cyclization carbonylation alkyne.
The palladium-catalyzed annulation of internal alkynes by o-iodophenols in the presence of CO results in exclusive formation of coumarins. No isomeric chromones have been observed The best reaction conditions utilize 2-iodophenol, 5 equiv of alkyne, 1 atm of CO, 5 mol % Pd(OAc)2, 2 equiv of pyridine, and 1 equiv of n-Bu4NCl in DMF at 120 °C. The use of a sterically unhindered pyridine base is essential to achieve high yields. A wide variety of 3,4-disubstituted coumarins containing alkyl, aryl, silyl, alkoxy, acyl, and ester groups have been prepared in moderate to good yields. Mixtures of regioisomers have been obtained when unsym. alkynes are employed. 2-Iodophenols with electron-withdrawing and electron-donating substituents and 3-iodo-2-pyridone are effective in this annulation process. For example, the reaction of 2-iodophenol with (1-butynyl)benzene gave a mixture of 4-ethyl-3-phenyl-2H-1-benzopyran-2-one and 3-ethyl-4-phenyl-2H-1-benzopyran-2-one. The reaction is believed to proceed via (1) oxidative addition of 2-iodophenol to Pd(0), (2) insertion of the alkyne triple bond into the aryl-palladium bond, (3) CO insertion into the resulting vinylic carbon-palladium bond, and (4) nucleophilic attack of the phenolic oxygen on the carbonyl carbon of the acylpalladium complex with simultaneous regeneration of the Pd(0) catalyst. This annulation process is the first example of intermol. insertion of an alkyne occurring in preference to CO insertion.
Journal of Organic Chemistry published new progress about Alkynes Role: RCT (Reactant), RACT (Reactant or Reagent). 112-63-0 belongs to class esters-buliding-blocks, and the molecular formula is C19H34O2, Computed Properties of 112-63-0.
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics