Biaryl Synthesis via Palladium-Catalyzed Aryne Multicomponent Coupling

Abstract

Aryl iodides have been introduced as electrophiles in the three-component Heck coupling of arynes. Following optimization studies to favor three- versus two-component coupling, the reaction proceeds in good yield to afford a variety of functionalized biaryls.

Palladium-Catalyzed Annulation of Arynes byo-Halobenzamides: Synthesis of Phenanthridinones

“…Reductive elimination gives rise to the arylpalladium(II) intermediate III . However, we cannot rule out the possibility that Pd(0) inserts directly into the C-Br bond of 1a to form the intermediate IV , which then undergoes carbopalladation of the aryne to give rise to intermediate III 21 (path b). Regardless of how the intermediate III is formed, under the basic conditions, it is expected to cyclize to the intermediate V .…”

Synthesis of 9-Fluorenylidenes and 9,10-Phenanthrenes through Palladium-Catalyzed Aryne Annulation by o-Halostyrenes and o-Halo Allylic Benzenes

“…Upon reductive elimination, complex II could afford a new arylpalladium intermediate III . Alternatively, according to path b, Pd(0) might add oxidatively to the aryl halide to afford the arylpalladium(II) intermediate IV , which in turn might add to the aryne32 to afford arylpalladium intermediate III . Regardless of how intermediate III is generated, the palladium-carbon bond in this intermediate can then add across the neighboring carbon-carbon double bond to afford intermediate V , which directly affords the fluorenylidene product by β-hydride elimination when n = 0.…”

Palladium‐Catalyzed Annulation of Acyloximes with Arynes (or Alkynes): Synthesis of Phenanthridines and Isoquinolines

“…Another catalytic cycle involving the h 2 -metallocyclopropene intermediate 9 may also be operative (see Scheme 2). [34] However, we believed that this kinetically viable pathway might not be responsible for the formation of the desired product. [35] Rather, it accounts for the formation of the side products such as triphenylene and 6-propylphenanthridine.…”