636562-54-4

Upstream product

• 930-96-1 3-bromo-2-thiophenecarboxaldehyde 
• 536-74-3 phenylacetylene 

Downstream Products

• 1083167-21-8 C₁₃H₁₀OS 
• 57279-48-8 5-phenylthieno[2,3-c]pyran-7(7H)-one 
• 1378284-33-3 2-ethynyl-3-(phenylethynyl)thiophene 
• 1431563-00-6 methyl 2-(hydroxy(2-(phenylethynyl)thiophen-3-yl)methyl)acrylate 

Relevant academic research and scientific papers

Exploiting Hydrazones to Improve the Efficiency of 6π-Electrocyclization Reactions of 1-Azatrienes

The greater geometric lability of hydrazones compared to that of oxime ethers is used as a basis to overcome the reluctance of Z-oxime ether azatrienes to undergo electrocyclization toward the synthesis of borylated (heteroaromatic) pyridines and ring-fused analogues. Such hydrazones now allow access to previously inaccessible tri- and tetrasubstituted 3-borylpyridines in high yields.

Gold-Catalyzed Formal Cyclisation/Dimerization of Thiophene-Tethered Diynes

A new pathway in dual gold-catalyzed reaction of thiophene-tethered diynes has been identified. A series of fully conjugated alkynyl-substituted benzothiophenes and benzofurans was obtained by a formal cyclisation/dimerization sequence. All the products are fluorescent, owing to their extended conjugation. The mechanistic studies have been carried out, suggesting that gold acetylides take part in this transformation.

Highly selective construction of medium-sized lactams by palladium-catalyzed intramolecular hydroaminocarbonylation of aminoalkynes

A novel palladium-catalyzed intramolecular hydroaminocarbonylation of aminoalkynes has been developed. This direct and operationally simple protocol provides a rapid and reliable approach to a diverse array of valuable seven-and eight-membered lactams with high chemoselectivity and regioselectivity. The high selectivity might be attributed to rational tuning the electronic nature of the amine moiety and the palladium catalyst which enabled this transformation to proceed in the absence of acidic or any other additives under fairly mild reaction conditions. This method paves the way for the synthesis of medium-sized lactams.

Gold-Catalyzed Ring Expansion of Enyne-Lactone: Generation and Transformation of 2-Oxoninonium

An efficient gold-catalyzed ring-expansion reaction of enyne-lactones to form 2-oxoninonium intermediates is reported. The 2-oxoninonium generated in this work could undergo further 6π electrocyclization and aromatization reaction to produce different aromatic compounds.

Access toward Fluorenone Derivatives through Solvent-Free Ruthenium Trichloride Mediated [2 + 2 + 2] Cycloadditions

An efficient and practical route for the preparation of highly substituted fluorenones and analogues via solvent-free ruthenium trichloride mediated [2 + 2 + 2] cycloaddition of α,-diynes and alkynes has been developed. This green chemistry approach involves a solventless and atom-economical catalytic process to generate densely functionalized fluorenones and related derivatives of high synthetic utility.

Efficient Pathway for the Preparation of Aryl(isoquinoline)iodonium(III) Salts and Synthesis of Radiofluorinated Isoquinolines

Iodonium compounds play a pivotal role in18F-fluorination of radiopharmaceuticals containing non-activated arenes. However, preparation of these species is limited to oxidation conditions or exchange with organometallics that are prepared from aryl halides. Herein we describe a novel “one-pot” process to assemble aryl(isoquinoline)iodonium salts in 40–94 % yields from mesoionic carbene silver complex and Aryl-I-Py2(OTf)2. The method is general, practical, and compatible with well-functionalized molecules as well as useful for the preparation of a wide range of18F-labeled isoquinolines resulting in up to 92 % radiochemical conversion. As proof of concept, a fluorinated isoquinoline alkaloid,18F-aspergillitine is prepared in 10 % isolated radiochemical yield from the corresponding phenyl(aspergillitine)iodonium salt.

Radical Cascade Cyclization: Reaction of 1,6-Enynes with Aryl Radicals by Electron Catalysis

The radical cascade cyclization of various 1,6-enynes with aryl radicals by electron catalysis under metal-free reaction conditions was explored. Readily available anilines were used as radical precursors, and the reactions proceeded in the absence of any transition metal. These cascades comprise three C–C bond formations, which provide polycyclic structures with extended π-systems. The photophysical properties of some of these novel compounds were investigated, and a plausible reaction mechanism is proposed.

Self-Relay Gold(I)-Catalyzed Pictet-Spengler/Cyclization Cascade Reaction for the Rapid Elaboration of Pentacyclic Indole Derivatives

Gold-catalyzed cascade reactions allow the rapid elaboration of pentacyclic indolo[2,3-a]quinolizidines from N-allyl tryptamines and ortho-alkynylarylaldehydes. The tandem process combines a gold-catalyzed Pictet-Spengler reaction and a cyclization occurring concomitantly with an allyl transfer from the nitrogen atom to the stilbene function. Various substituted allyls were successfully transferred, furnishing the products in yields typically ranging from 60-98 % in high diastereoselectivity. Tryptamines bearing a butenol chain undergo an additional cyclization to chiral hemiaminals in high diastereoselectivities. Going for gold! Gold-catalyzed cascade reactions allow the rapid elaboration of pentacyclic indolo[2,3-a]quinolizidines from N-allyl tryptamines and ortho-alkynylarylaldehydes (see scheme). The tandem process combines a gold-catalyzed Pictet-Spengler reaction and a cyclization occurring concomitantly with an allyl transfer from the nitrogen atom to the stilbene function.

One-pot concise syntheses of benzimidazo[2,1-a]isoquinolines by a microwave-accelerated tandem process

Direct, efficient syntheses of the benzimidazo[2,1-a]isoquinoline ring system have been achieved with 2-bromoarylaldehydes, terminal alkynes, and 1,2-phenylenediamines by a microwave-accelerated tandem process in which a Sonogashira coupling, 5-endo cyclization, oxidative aromatization, and 6-endo cyclization can be performed in a single synthetic operation.

Iodine-mediated electrophilic cyclization of 2-alkynyl-1-methylene azide aromatics leading to highly substituted isoquinolines and its application to the synthesis of norchelerythrine

The reaction of 2-alkynyl-1-methylene azide aromatics 1 with iodine and/or other iodium donors, such as the Barluenga reagent (Py2IBF 4/HBF4) and NIS, gave highly substituted cyclization products, namely, the 1,3-disubstituted 4-iodoisoquinolines 2, in good to high yields. Not only simple 2-alkynyl benzyl azides 1a-j and their substituted analogues 1k-u and 6 but also heteroaromatic analogues, including pyridine 8, pyrroles 10a-c, furane 10d, and thiophenes 10e-g, gave the corresponding isoquinoline derivatives in excellent to allowable yields. Electron-donating and electron-accepting substituents on the aromatic ring were equally tolerated, and either acidic or basic (or even neutral) reaction conditions, depending on the reactivity of the substrate, could be applied to smoothly convert the azide starting materials into the desired isoquinoline products in moderate to good yields. Limits were found only in connection with the substituent at the alkyne terminus, where electron-neutral or electron-donating substituents are clearly favored. The iodine-mediated electrophilic cyclization of 1 most probably proceeds through the iodonium ion intermediate 4 followed by nucleophilic cyclization of the azide and subsequent elimination of N2. This new methodology was successfully applied to the short synthesis of norchelerythrine.