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Upstream product

• 32768-54-0 2,3-dichlorotoluene 
• 501-65-5 diphenyl acetylene 
• 108-88-3 toluene 
• 4792-30-7 3-methylphthalic acid anhydride 
• 95-46-5 2-methylphenyl bromide 
• 16419-60-6 2-Methylphenylboronic acid 
• 101300-65-6 1,2-bis(trimethylsilyl)-3-methylbenzene 
• 479-33-4 2,3,4,5-tetraphenylcyclopenta-2,4-dienone 
• 76054-67-6 (1R,8S)-3,11,11-Trimethyl-1,8,9,10-tetraphenyl-11-germa-tricyclo[6.2.1.0^2,7]undeca-2⁽⁷⁾,3,5,9-tetraene 
• 5100-98-1 1-chloro-2-iodo-3-methylbenzene 

Relevant academic research and scientific papers

Group 4 Diarylmetallocenes as Bespoke Aryne Precursors for Titanium-Catalyzed [2 + 2 + 2] Cycloaddition of Arynes and Alkynes

Despite the ubiquity of reports describing titanium (Ti)-catalyzed [2 + 2 + 2] cyclotrimerization of alkynes, the incorporation of arynes into this potent manifold has never been reported. The in situ generation of arynes often requires fluoride, which instead will react with the highly fluorophilic Ti center, suppressing productive catalysis. Herein, we describe the use of group 4 diarylmetallocenes, CpR2MAr2 (CpR = C5H5, C5Me5; M = Ti, Zr), as aryne precursors for the Ti-catalyzed synthesis of substituted naphthalenes via coupling with 2 equiv of an alkyne. Fair-to-good yields of the desired naphthalene products could be obtained with 1% catalyst loadings, which is roughly an order of magnitude lower than similar reactions catalyzed by palladium or nickel. Additionally, naphthalenes find broad applications in the electronics, photovoltaics, and pharmaceutical industries, urging the discovery of more economic syntheses. These results indicate that aryne transfer from a CpR2M(?2-aryne) complex to another metal is a viable route for the introduction of aryne fragments into organometallic catalytic processes.

Solvent free, phosphine free Pd-catalyzed annulations of aryl bromides with diarylacetylenes

Palladium nanoparticles and sodium acetate catalyze the reaction of aryl bromide with diarylacetylene to produce annulated products in good yield. One equivalent of PEG-600 serves as the solvent. This procedure is compatible with a wide variety of functional groups.

Three-bond breaking of cyclic anhydrides: Easy access to polyfunctionalized naphthalenes and phenanthrenes

Benzannulation of phthalic anhydrides with alkynes to polyfunctionalized naphthalenes and phenanthrenes was confirmed to be straightforward using a palladium catalytic system. Sequential liberation of CO2 and CO occurred via oxidative decomposition of anhydride. In the case of 1,8-naphthalenedicarboxylic anhydrides, both aryls were encompassed in the annulation reaction to afford acenaphthylenes.

Synthesis of highly substituted acenes through rhodium-catalyzed oxidative coupling of arylboron reagents with alkynes

The rhodium-catalyzed oxidative 1:2 coupling reactions of arylboronic acids or their esters with alkynes smoothly proceed to produce the corresponding annulated products. Of special note, highly substituted, readily soluble, and tractable anthracene and tetracene derivatives can be obtained selectively from 2-naphthyl- and 2-anthrylboron reagents, respectively.

Synthesis of highly substituted naphthalene and anthracene derivatives by rhodium-catalyzed oxidative coupling of arylboronic acids with alkynes

The rhodium-catalyzed oxidative 1:2 coupling reactions of arylboronic acids with alkynes effectively proceeds in the presence of a copper-air oxidant to produce the corresponding annulated products. Of special note, anthracene derivatives can be obtained

Palladium-catalyzed formation of highly substituted naphthalenes from arene and alkyne hydrocarbons

Several highly substituted naphthalenes 3 have been synthesized in a one-pot reaction by treatment of arenes 1 with alkynes 2 in the presence of palladium acetate and silver acetate. In this Pd-catalyzed protocol, an arene provides a benzo source for the construction of a naphthalene core through twofold aryl C - H bond activation. Reaction of triphenylphosphine with diphenylethyne (2 a) under the catalysis of PdIV complexes produced 1,2,3,4-tetraphenylnaphthalene (3ba) in 62% yield. Here, triphenylphosphine undergoes one aryl C - P bond cleavage and one aryl C - H bond activation to serve as a benzo moiety. Crystal structures of cycloadducts 3ea, 3ga, and 3ac have been analyzed. The twisted naphthalenes arise not only from the overcrowded substituents but also from the contribution of the CH3-π interaction.

A new and efficient hypervalent iodine-benzyne precursor, (phenyl)[o- (trimethylsilyl)phenyl]iodonium triflate: Generation, trapping reaction, and nature of benzyne

A new and efficient hypervalent iodine-benzyne precursor, (phenyl)[2- (trimethylsilyl)phenyl]-iodonium triflate (10), is reported. The hypervalent iodine-benzyne precursor 10 is readily prepared by reaction of 1,2- bis(trimethylsilyl)benzene with a PhI(OAc)2/TfOH reagent system. Treatment of 10 with Bu4NF in CH2Cl2 at room temperature gives high yields of the benzyne adducts in the presence of a trapping agent such as furan, 2- methylfuran, anthracene, tetraphenylcyclopentadienone, or 1,3- diphenylisobenzofuran. Especially, the result of the reaction in the presence of furan indicates a quantitative generation of benzyne and its efficient capture by the furan. Similarly, methylbenzynes (22 and 27) are efficiently generated from the corresponding methyl-substituted (trimethylsilyl)phenyliodonium triflates (12 and 13). The preparation of the hypervalent iodine-benzyne precursors, the generation of benzynes, the trapping reactions, and the nature are described in detail together with the advantages of the present reagents over the previously reported benzyne precursors.

7-GERMANORBORNADIENES AND THEIR THERMAL CYCLOELIMINATIONS

7 new 7-germanorbornadienes, crystalline and stable at 25 deg C, have been prepared by Diels-Alder reaction.They decompose thermally via a two step mechanism with an intermediate biradical, forming the benzene derivative and germylenes, R2Ge.