A brand-new Pd-mediated generation of benzyne and its [2+2+2] cycloaddition: δ-carbon elimination and concomitant decarboxylation

Studies on Naturalp-Terphenyls: Total Syntheses of Vialinin A and Terrestrin B

“…These compounds seemed to be produced through ligand exchange between intermediary Ar-Pd-OTf and TfOPd-OMOM generated from this by the elimination of a benzyne. 34) Among the three types of boronic acid used, benzyl derivative 8 proved to be unsuitable in this coupling reaction.…”

Recent advances in fluoride-free aryne generation from arene precursors

“…Catalytic aryne generation has emerged in recent years as an attractive strategy to access transition metal-associated arynes, with a few pioneering reports having demonstrated this principle. [36][37][38]40 As the metal can initiate both aryne formation and catalyse subsequent bond-forming transformations, the generation of metal-associated arynes is This journal is © The Royal Society of Chemistry 20xx…”

“…In 2008, Kim and co-workers established that certain orthobromobenzoates generate triphenylenes under Pd catalysis, with an aryne intermediate suggested to account for the products. 36 Oxidative addition into the C-X bond of orthohalobenzoate 90 is believed to be followed by δ-carbon elimination and loss of CO2 from arylpalladium intermediate 91 to generate Pd-associated aryne 92 (Scheme 14a). Triphenylene 93 is then the product of a Pd-catalysed [2+2+2] cyclotrimerisation of Pd-aryne 92, 3a with the active catalyst regenerated by reductive elimination of the corresponding alkyl halide ('RX').…”

4.09 Nucleophilic Coupling with Arynes

“…98 Various benzoannulated oxygen heterocycles have been synthesized based on this protocol by use of 1-aminobenzotriazoles bearing a hydroxy group in a side chain via intramolecular aryne cyclization (see Section 4.09.3.2.6). 100 can also serve as precursors of arynes under palladium catalysis via a decarboxylation reaction. Although these methods opened up a new vista of the catalytic generation of arynes from readily available substrates, their utilization for nucleophilic coupling should be difficult because the resulting arynes undergo the palladiumcatalyzed self-trimerization succeedingly (Scheme 14).…”