- Nickel-catalyzed formation of cyclopentenone derivatives via the unique cycloaddition of α,β-unsaturated phenyl esters with alkynes
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Oxygen-containing organic compounds, such as ethers, carboxylates, and carbamates, have recently received increasing attention because of their newly discovered applications as electrophiles in cross-coupling reactions via transition metal-catalyzed C-O bond activation. However, no cycloaddition reaction involving their C-O bond activation has been demonstrated thus far. The present study developed a Ni(0)-catalyzed unique [3+2] cycloaddition reaction of α,β-unsaturated phenyl esters with alkynes in iPrOH to yield cyclopentenone derivatives.
- Ohashi, Masato,Taniguchi, Tomoaki,Ogoshi, Sensuke
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supporting information; experimental part
p. 14900 - 14903
(2011/11/01)
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- A Pauson-Khand-type reaction between alkynes and olefinic aldehydes catalyzed by rhodium/cobalt heterobimetallic nanoparticles: An olefinic aldehyde as an olefin and CO source
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Co/Rh (Co:Rh = 2:2) heterobimetallic nanoparticles derived from Co 2Rh2(CO)12 react with alkynes and α,β-unsaturated aldehydes such as acrolein, crotonaldehyde, and cinnamic aldehyde and release products resulting from [2 + 2 + 1]cycloaddition of alkyne, carbon monoxide, and alkene. α,β-Unsaturated aldehydes act as a CO and alkene source. These reactions produce 2-substituted cyclopentenones.
- Park, Kang Hyun,Jung, Il Gu,Chung, Young Keun
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p. 1183 - 1186
(2007/10/03)
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- Photochemistry of Cyclopropene Derivatives. Synthesis and Photorearrangement of a 3-Acyl-Substituted Cyclopropene
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Two different approaches toward the synthesis of a 3-acyl-substituted 1,2,3-triphenylcyclopropene were investigated.The first involved treating triphenylcyclopropenyl perchlorate with the anion derived from 1,3-dithiane followed by hydrolysis of the resulting dithioacetal.Unfortunately, all attempts to obtain a carbonyl compound from the hydrolysis failed.The only product obtained corresponded to a 1,2-diphenyl-1,2-diacyl-substituted alkene.The second approach utilized for the synthesis involved treating 3-cyano-1,2,3-triphenylcyclopropene with methyllithium.The addition proceeded quite smoothly to give the desired 3-acetyl derivative in high yield.Irradiation of 1,2,3-triphenyl-3-acetylcyclopropene in benzene afforded a mixture of 2,3,4-triphenyl-2-cyclopentenone (60percent), 2-methyl-3,4,5-triphenylfuran (27percent), and 3-acetyl-1,2-diphenylindene (13percent).The formation of the three products obtained can be rationalized in terms of a vinylcarbene intermediate.Several different pathways are available to this species, depending on the stereochemistry about the double bond and on the conformation the oxygen atom assumes in the cis intermediate.The formation of the 2-cyclopentenone derivative provides good support for the mechanism proposed some years ago to rationalize the photochemical rearrangement of 2,5-dimethylfuran.
- Padwa, Albert,Akiba, Mitsuo,Chou, Chuen S.,Cohen, Leslie
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p. 183 - 191
(2007/10/02)
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