52264-93-4

Upstream product

• 98590-56-8 (3,3-dibromo-allyl)-phenyl ether 
• 13610-02-1 1-phenoxy-2-propyne 
• 139-02-6 sodium phenoxide 
• 41876-99-7 1-iodo-2-(2-propynyloxy)benzene 
• 108-95-2 phenol 

Downstream Products

• 30518-54-8 3-bromo-2H-chromene 
• 30518-52-6 4-bromo-2H-chromene 
• 122323-21-1 ((Z)-2,3-Dibromo-allyloxy)-benzene 
• 491-37-2 2,3-dihydro-4H-1-benzopyran-4-one 
• 853304-42-4 4-bromo-3-phenyl-2H-chromene 
• 853304-41-3 4-bromo-3-(2-p-tolyl-vinyl)-2H-chromene 
• 5882-22-4 4-(4-methoxy-phenyl)-3-phenyl-2H-chromene 
• 1574562-67-6 C₂₀H₁₇NOS 

Relevant academic research and scientific papers

Iron-Mediated Cyclization of 1,3-Diynyl Propargyl Aryl Ethers with Dibutyl Diselenide: Synthesis of Selenophene-Fused Chromenes

The synthesis of selenophene-fused chromene derivatives starting from 1,3-diynyl propargyl aryl ethers is reported herein. The method is based on carbon-carbon, carbon-selenium, selenium-carbon and carbon-selenium bonds formation in a one-pot protocol, using iron(III) chloride and dibutyl diselenide as promoters. The same reaction conditions were applied to propargyl anilines leading to the formation of 1-(butylselanyl)-selenophene quinolines. The results showed that the dilution and temperature of substrate addition had a crucial influence in the products obtained. When the substrates were added at room temperature, in the absence of a solvent, a mixture of products was obtained, whereas the slowly addition (15 min) of starting materials, as a dichloromethane solution, at 0 °C led to the product formation in good yields. The mechanistic study indicates that the cooperative action between iron(III) chloride and dibutyl diselenide was essential to promote the cyclization, whereas separately none of them was effective in promoting the cyclization. We proved the synthetic utility of heterocycles obtained in the Suzuki cross coupling reaction, giving the corresponding cross-coupled products in good yields. In addition, the organoselenium moiety was removed from the structures of products by using n-butyllithium. (Figure presented.).

Nickel-Catalyzed Reductive 1,2-Dialkynylation of Alkenes Bearing an 8-Aminoquinoline Directing Group

An unprecedented nickel-catalyzed reductive 1,2-dialkynylation of alkenes bearing an 8-aminoquinoline directing group has been developed. This method proceeded through a migratory insertion/reductive-coupling process under mild conditions with a wide substrate scope and good functional group tolerance, providing direct access to the synthetically flexible 1,5-diynes. Moreover, the 1,2-dialkynylation products could be further converted to borate-ester- or azide-functionalized 1,5-dienes, ditriazole, β-diyne primary amide, and trisubstituted benzene.

Influence of the acetylenic substituent on the intramolecular carbolithiation of alkynes

The intramolecular carbolithiation of a series of propargylic ethers has been performed to evaluate the influence of the terminal substituent on the efficiency and the stereochemical outcome of the cyclization. Our results show that only 5-exo-dig cyclizations are observed, and dihydrobenzofurans are obtained exclusively. Depending on the nature of the terminal substituent, two cases can be considered. If the terminal substituent carried by the acetylenic carbon atom is itself a carbon atom, the cyclization can occur provided the terminal propargylic position bears a coordinating element and is at least disubstituted. When the cyclization occurs, it follows an anti-carbolithiation pathway and thus leads to the E isomer of the exocyclic double bond. Only in one case (Ph) was a mixture of the E and Z isomers of the resulting olefin recovered. The cyclization can also take place if the alkyne is directly substituted by S or Si, provided the cyclization conditions are tuned. In the case of the trimethylsilyl substituent, a syn-carbolithiation was observed. If the double bond is recovered, in most cases, in the exocyclic position, the products can aromatize directly for SPh-substituted substrate 24. Furthermore, in the two latter cases, when alkylation of the vinyllithium intermediate is performed, isomerization of the double bond seems instantaneous. Copyright

Convenient preparation of bromoalkynes from primary alkynes and PPh3/CBr4

1-Bromo-1-alkynes are prepared in high yields under very mild conditions by treatment of primary alkynes with PPh3/CBr4.

THERMAL BEHAVIOUR OF ARYL γ-HALOPROPARGYL ETHERS

A systematic study of the behaviour of aryl γ-halopropargyl ethers under thermal condition was undertaken.Aryl γ-bromopropargyl ethers 2 underwent unique transformation in N,N-diethylaniline (215 deg C, 6 h) giving rise to a mixture of products 3,4 and 5,whereas, under similar conditions aryl γ-chloropropargyl ethers 8, afforded 4-chlorochromenes, 9.A remarkable substituent and solvent effect has been observed in the thermolysis of these aryl γ-bromo and γ-chloropropargyl ethers, rendering this transformation as a method for the synthesis of a number of substituted 4-bromochromenes 3, 4-chlorochromenes 9 and chroman-4-ones 7.In contrast, solution thermolysis of aryl γ-iodopropargyl ether 11 afforded aryl propargyl ether 1 as the major product.