paper describes the preparation of indoles, azaindoles and benzofurans in pure water by using a new heterogeneous Pd-Cu/C catalyst through a cascade Sonogashira alkynylation-cyclization sequence. Details of the optimization studies and the substrate scope are discussed. This procedure allows the preparation of heterocycles with good yields and is tolerant to a wide variety of functional groups.
A Pd‐catalyzed efficient reductive cross‐coupling reaction without metallic reductant to construct a Csp2Csp3 bond has been reported. A PdIV complex was proposed to be a key intermediate, which subsequently went through double oxidative addition and double reductive elimination to produce the cross‐coupling products by involving Pd0/II/IV in one transformation. The oxidative addition from PdII to
Synthesis of Benzofurans and Indoles from Terminal Alkynes and Iodoaromatics Catalyzed by Recyclable Palladium Nanoparticles Immobilized on Siliceous Mesocellular Foam
作者:Alexandre Bruneau、Karl P. J. Gustafson、Ning Yuan、Cheuk-Wai Tai、Ingmar Persson、Xiaodong Zou、Jan-E. Bäckvall
DOI:10.1002/chem.201702614
日期:2017.9.18
(Pd0‐AmP‐MCF), for the synthesis of heterocycles. Reaction of o‐iodophenols and protected o‐iodoanilines with acetylenes in the presence of a Pd nanocatalyst produced 2‐substituted benzofurans and indoles, respectively. In general, the catalytic protocol afforded the desired products in good to excellent yields under mild reaction conditions without the addition of ligands. Moreover, the structure
Palladium-Catalyzed Annulations of Strained Cyclic Allenes
作者:Andrew V. Kelleghan、Dominick C. Witkowski、Matthew S. McVeigh、Neil K. Garg
DOI:10.1021/jacs.1c04896
日期:2021.6.30
We report Pd-catalyzed annulations of in situ generated strained cyclic allenes. This methodology employs aryl halides and cyclic allene precursors as the reaction partners in order to generate fused heterocyclic products. The annulation proceeds via the formation of two new bonds and an sp3 center. Moreover, both diastereo- and enantioselective variants of this methodology are validated, with the
One-Pot Synthesis of Heteroatom-Bridged Cyclic Diaryliodonium Salts
作者:Mattis Damrath、Lucien D. Caspers、Daniel Duvinage、Boris J. Nachtsheim
DOI:10.1021/acs.orglett.2c00691
日期:2022.4.8
Two one-pot procedures for the construction of O- and N-bridged diaryliodonium triflates are described. An effective aryne-mediated arylation of o-iodophenols and -sulfonamides provides diarylether and diarylamine intermediates, which are subsequently oxidized and cyclized to the corresponding diaryliodaoxinium and -iodazinium salts. Different derivatizations were applied to demonstrate their capacity