Palladium‐Catalyzed Annulation of vic‐Bis(pinacolatoboryl)alkenes and ‐phenanthrenes with 2,2′‐Dibromobiaryls: Facile Synthesis of Functionalized Phenanthrenes and Dibenzo[g,p]chrysenes

Abstract

Double‐cross: An annulation approach to functionalized polycyclic aromatic hydrocarbons involving a palladium‐catalyzed double cross‐coupling reaction of vic‐diborylalkenes and ‐phenanthrenes with 2,2′‐dibromobiaryls led to a variety of phenanthrenes and dibenzo[g,p]chrysenes, as well as [5]helicenes, dithienobenzenes, and triphenyleno[1,2‐b:4,3‐b′]dithiophenes (see scheme; Bpin=pinacolatoboryl).

Synthesis, Crystal Packing, and Ambipolar Carrier Transport Property of Twisted Dibenzo[g,p]chrysenes

“…After concentration in vacuo, purification by flash column chromatography on silica gel (eluent: n ‐hexane) afforded the title compound ( 2 , 30 mg, 89 %) as a colorless solid. Analytical data were in good accordance with data reported in the literature 10a…”

Regioselective Synthesis of Fused Furans by Decarboxylative Annulation of α,β‐Alkenyl Carboxylic Acid with Cyclic Ketone: Synthesis of Di‐Heteroaryl Derivatives

“…Thec arboxylic acid group not only serves as al eaving group in decarboxylative reactions,b ut can be employed as ad irecting group in cross-coupling reactions. [10] Heteroarenes are key structural motifs in av ariety of natural products and biologically active compounds.F or instance,f unctionalized fused furan derivatives represent an elegant class of Oheterocycles with wide range of applications in pharmaceuticals and agrochemicals research. [8] Decarboxylative annulation reactions have recently been studied comprehensively for the synthesis of polynuclear aromatic hydrocarbons [8b, 9] and heteroarenes.…”

MPHT‐Promoted Bromocyclization of ortho‐Substituted Arylalkynes: Application to the Synthesis of 2‐Substituted 3‐Bromobenzofurans and ‐Benzo[b]thiophenes

“…of MPHT ( Table 2, Entries 1 and 2). We were pleased to observe the quantitative formation of bis(3-bromobenzofuran) 4a and bis(3-bromobenzothiophene) 4b, which were used as starting materials for the synthesis of benzannulated phospholes, [15] dibenzothienopyrroles, [16] dithienosiloles, [17] and functionalized phenanthrenes [18] of physical interest. Unsymmetrical diyne 3c reacted cleanly with MPHT to afford expected heterocycle 4c, again with excellent yield (Table 2, Entry 3).…”