Rapid Access to Bi‐ and Tri‐Functionalized Dibenzofurans and their Application in Selective Suzuki–Miyaura Cross Coupling Reactions

Abstract

Syntheses of 1,2‐, 1,3‐, 1,4‐, 1,8‐, 2,4‐, 3,4‐, 4,8‐, 1,2,4‐, 1,2,8‐ and 1,3,4‐functionalized dibenzofurans in few steps with good to excellent yields starting from dibenzofuran‐1‐ol or ‐4‐ol are presented. These rapidly accessible bi‐ or tri‐functionalized building blocks are of great interest for the synthesis of bioactive substances or functional material development. Furthermore, for intermediates containing both a bromine and a triflate moiety, a selective mono‐substitution by means of Suzuki–Miyaura reaction (SMR) is described.

Selective Synthesis of Bioderived Dibenzofurans and Bicycloalkanes from a Cellulose-Based Route

“…Hydroxylated dibenzofuran can be an excellent motif because it is readily grafted and modified by methods such as borylation, esterification, and halogenation to produce a variety of functionalized dibenzofurans. 59,60 Synthesis of Bicycloalkanes. The hydrodeoxygenation of THBF to bicycloalkanes was catalyzed by acidic zeolites and Pd/C catalysts.…”

“…The C–C oxidative coupling and dehydration reaction show a high yield and easy separation of dibenzofuran hydroxylated derivatives. Hydroxylated dibenzofuran can be an excellent motif because it is readily grafted and modified by methods such as borylation, esterification, and halogenation to produce a variety of functionalized dibenzofurans. , …”

Chemodivergence between Electrophiles in Cross‐Coupling Reactions

“… [39] A bulky monodentate phosphine (P t Bu 3 ) promotes C−Br cleavage to give 15 b , but use of the smaller phosphine PPh 3 leads to C−OTf cleavage ( 15 a ). König showed that 8‐bromo‐1‐trifloyldibenzofurans, substrates that are electronically activated toward oxidative addition at C1, also undergo Suzuki–Miyaura cross‐coupling with ligand‐dependent selectivity [40] . Clearly, substrate structure can determine the extent to which ligands influence chemoselectivity.…”

“…Kçnigs howed that 8-bromo-1-trifloyldibenzofurans, substratest hat are electronically activated toward oxidative addition at C1, also undergo Suzuki-Miyaura cross-coupling with ligand-dependent selectivity. [40] Clearly, substrate structure can determine the extentt ow hich ligands influence chemoselectivity.…”

Palladium‐Catalyzed Chemoselective Borylation of (Poly)halogenated Aryl Triflates and Their Application in Consecutive Reactions

“…[6b] Despite the limitation of the substrate scope, fragmentary examples were limited to following the classical reactivity order of ArÀ I > ArÀ Br [7] or ArÀ Br > ArÀ OTf. [8] To the best of our knowledge, there is no report of a transitionmetal-catalyzed chemoselective borylation reaction using chloroaryl triflates in CÀ Cl over CÀ OTf bonds.…”