17684-01-4Relevant academic research and scientific papers
Palladium-catalyzed regio- and stereoselective cross-addition of terminal alkynes to ynol ethers and synthesis of 1,4-enyn-3-ones
Haribabu, Madala,Dwivedi, Vikas,Kant, Ruchir,Sridharreddy, Maddi
, p. 3783 - 3786 (2015)
Conjugated enynes, enol ethers, and enynones are versatile building blocks that can be elaborated by a wide variety of synthetic transformations. The selective synthesis of such units is a prerequisite for their effective utilization. The synthesis of conjugated 2-phenoxyenynes through a palladium-catalyzed cross-addition of terminal alkynes to phenylethynyl ethers (hydroalkynylation) is now presented. The reaction is highly regio-, stereo-, and chemoselective, and shows excellent tolerance toward functional groups. The addition further features very mild reaction conditions (room temperature) and an inexpensive catalytic system (without a ligand and with a cheaply available Pd catalyst). The thus synthesized enynyl ethers with allylic hydroxy tethers, which survived the reaction, were shown to be ready precursors for valuable 1-en-4-yn-3-ones. Alkyne plus alkyne: The hydroalkynylation of phenoxy alkynes was achieved with high regio-, chemo-, and stereoselectivities. A catalytic amount of [Pd(PPh3)2Cl2] with 2.5equiv. of NEt3 could mediate the reaction without the need for a ligand, or a Cu catalyst for the activation of the terminal alkyne. The products with allylic hydroxy tether are convenient precursors for useful enynones. pTSA=p-toluenesulfonic acid.
New synthetic approach for the construction of multisubstituted 2-acyl furans by the IBX-mediated cascade oxidation/cyclization of cis-2-En-4-yn-1-ols (IBX = 2-iodoxybenzoic acid)
Du, Xiangwei,Chen, Haoyi,Liu, Yuanhong
supporting information; experimental part, p. 9495 - 9498 (2009/10/06)
A new approach for the construction of multisubstituted 2-acyl furans through cis-2-En-4-yn-1-ols (IBX=2-iodoxybenzoic acid)-mediated oxidation/cyclization in dimethyl sulfoxidse (DMSO) was developed. The results show that the introduction of an alkyl group at Cl provided a satisfactory yield of furan of 60% at 90°C. It is seen that IBX act as an electrophile to promote the cycloaddition of carbonyl group to the alkyne moiety. The furan derivatives are found to be useful synthetic intermediates for access to the compounds bearing biological activity. The studies also elucidate this reaction mechanism and extend the scope of synthetic utility of multisubstituted 2-acyl furans.
