Alkynylarene

A versatile and regioselective synthesis of benzo[b]furans, naphthalenes, indoles and benzothiophenes was achieved by reaction of o-alkynylarene and heteroarene carboxaldehyde derivatives in the presence of iodonium ions. The reaction mechanism was also discussed <06CEJ5790>. 

Reactions of Fischer carbene complexes with diynes have been extensively studied as a synthetic approaches to alkynylarenes and biaryls. In general, Cr =C(0R )R (C0>5 (R = Me, Bu R = Ph, 1-nap, 1-cyclohexenyl) react with... 

Some novel silicon-containing arene-chromium tricarbonyl complexes (IV-VII), derived from phenyl-substituted silacyclobutanes (118), 1,1-dimethylsilaindane (120) and alkynylarenes (45), have been prepared by essentially identical methods. It is worth mentioning here that the organosilicon complex (VI) is somewhat more thermally stable than the silicon-free 1,1-dimethylindane complex (120). 

Analogously, the reaction of 2-bromophenyl-A-methylsulfoximine 432 with terminal alkynes in the presence of a palladium catalyst results in the formation of both 1,2-benzothiazine 433 and 1,2-benzisothiazoles 434. A preference for the former is seen with alkylalkynes while the latter are preferentially formed with alkynylarenes <20050L143>. 

Stille-type coupling in the presence of Nifacaclj-DIBALH and an additive (e.g., PhjP) provides styrenes and alkynylarenes. ... 

Arenes from enynes and diynes. A novel synthesis of alkynylarenes by the intermolecular cycloaddition of enynes and diynes has been developed. With enynes alone the products are 2,6-disubstituted styrenes which are formed by cyclodimerization. Note that benzynes undergo trimerization to give triphenylenes in situ, e.g., by treatment of o-trimethylsilylphenyl triflate with CsF in the presence of (PhjPl.Pd. ... 

Tab. 8.13 Indium-mediated palladium-catalyzed reaction of alkynylarene, allene, and aldehydes...

Hydrofluorination of alkynylarenes delivers (Z)-p-fluorostyrenes on treatment with 3HF Et3N and catalytic amounts of the Au complex. ... 

Addition and cycloaddition. Styrenes are transformed into benzylatnine derivatives by hydroamination with TsNH2/" More unusual is the regioselective addition of arenes across the triple bond of an alkynylarene, as catalyzed by FeCls. ... 

A synthesis of 9-alkylidene-9//-fluorenones from Arl and alkynylarenes involves a... 

A route to alkynylarenes and enynes from 1-alkynes involves formation of alkynylboronic esters [lithioalkynes -I- (/-PrOl B] and Suzuki coupling in situ. Suzuki cross-coupling using thallium(I) ethoxide as promoter is superior to TlOH because of its stability, commercial availability, and ease of use. A convenient method for assembling conjugated polyenes is assured. 

Coupling of alkynes with unsaturated halides. This coupling represents the simplest stereoselective assembly of alkynylarenes and enynes, - An amine is also added to neutralize the liberated acid. 

Alkynylarenes. Coupling of an alkyne with a haloarene in aqueous DME occurs in the presence of Pd/C, PPhj, Cul, and K CO,. 

Alkynylarenes. The catalyst system, usually in combination with a mild base (trialkylamine or KjCOj), is used to couple terminal alkynes with aryl iodides and triflates. A large rate enhancement is observed when an iodide salt is added, as shown in a synthesis of 1,2-bis(trimethylsilylethynyl)benzene. ... 

Starting from benzylaminopolystyrene, the diverse o-haloaryl resins 11 are prepared from substituted o-haloanilines. Pd-catalyzed cross-coupling under standard conditions with different alkynes affords o-alkynylarene resins 12. Copper is omitted... 

Bismuth Dual activation via t7,ar-chelation (276) has been implicated in the new car-boarylation of alkynylarenes (274) (X = 0, NTs, CR2) with Al,0-acetals (275), catalysed by Bi(OTf)3, which produces (277). The same reaction can also be catalysed by... 

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