- KOt-Bu/DMF promoted intramolecular cyclization of 1,1′-biphenyl aldehydes and ketones: An efficient synthesis of phenanthrenes
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A new synthesis of phenanthrene derivatives has been achieved through intramolecular cyclization of 1,1′-biphenyl aldehydes and ketones promoted by KOt-Bu/DMF. A free radical reaction pathway is proposed.
- Chen, Yan-Yan,Zhang, Niu-Niu,Ye, Lin-Miao,Chen, Jia-Hua,Sun, Xiang,Zhang, Xue-Jing,Yan, Ming
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p. 48046 - 48049
(2015/06/16)
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- Degenerate β-Aryl Rearrangements in Photochemically Generated Triarylvinyl Cations
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Irradiation of triphenyl- (1a), tri-p-tolyl (1b),or tri-p-anisylvinyl bromide (1c) in methanol gave the vinyl ethers 4 and the phenanthrenes 5.A study of -labeled bromides showed that β-aryl rearrangements takes place in the photochemically generated vinyl cations 3*.Irradiation of triaryl bromides 1* in trifluoroethanol and analysis of the extent of scrambling from C-2 to C-1 in the trifluoroethyl vinyl ethers 8 showed 38percent, 72percent, and 92percent rearrangement of the 13C label for 1a*, 1b*, and 1c*, respectively.Similar irradiation of 1* in methanol resulted in no rearrangement in 4.The results are discussed in relation to the nature of the solvent, the stability of the triarylvinyl cations, and the migratory aptitudes of the aryl groups.The behavior of the photochemically and thermally generated ions was compared.
- Kitamura, Tsugio,Kobayashi, Shinjiro,Taniguchi, Hiroshi,Fiakpui, Charles Y.,Lee, Choi Chuck,Rappoport, Zvi
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p. 3167 - 3170
(2007/10/02)
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