- Convenient synthesis of aryl substituted 3-hexene-1,5-diynes
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Dimerization of alkynyl carbenes generated from the reaction of 1,1-dibromo-2,3-diarylcyclopropanes (aryl=phenyl, 4-methylphenyl, 4-chlorophenyl) with a strong base under phase-transfer conditions occurs to give E- and Z-1,3,4,6-tetraaryl-3-hexene-1,5-diy
- Isagawa, Kakuzo,Mizuno, Kazuhiko,Majima, Tetsuro
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- Alkynylzirconation of alkynes and application to one-pot bisalkynylation of alkynes
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Stereocontrolled alkynylzirconation of unactivated alkynes was achieved by the reaction of an alkyne with Cp2ZrEt2 and alkynyl halide in this order. After hydrolysis of the alkynylzirconation product, trisubstituted enyne derivatives were obtained in good yields. Functionalized enynes were also prepared by the reaction of the alkynylzirconation products with a variety of electrophiles. Subsequent addition of the second alkynyl halide to the alkynylzirconation products provided an in situ protocol for bisalkynylation of alkynes into (Z)-enediynes in good yields.
- Liu, Yuanhong,Zhong, Zhenqi,Nakajima, Kiyohiko,Takahashi, Tamotsu
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- Enediynes from aza-enediynes: C,N-dialkynyl imines undergo both aza-Bergman rearrangement and conversion to enediynes and fumaronitriles
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Aza-enediynes (C,N-dialkynyl imines) undergo thermal aza-Bergman rearrangement to β-alkynyl acrylonitriles through 2,5-didehydropyridine (2,5-ddp) intermediates. Certain aza-enediynes also undergo an alternative process affording enediynes and fumaronitri
- Feng, Liping,Zhang, Aibin,Kerwin, Sean M.
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p. 1983 - 1986
(2007/10/03)
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- Synthesis and reactivity of allenes substituted by selenenyl groups at 1- and 3-positions
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1,3-Bis(methylseleno)- and 1,3-bis(benzylseleno)-l,3-diphenylpropadienes were synthesized by reaction of Ph2C3 dianion, prepared from 1,3-diphenylpropyne and n-butyllithium, with dimethyl diselenide or benzylselenocyanate in the presence of TMEDA, and reaction of the dianion with a mixture of dimethyl diselenide and benzylselenocyanate yielded 1-benzylseleno-3-methylselenoallene along with the symmetric allenes. Diselenocyclic allenes and tetraselenocyclic bisallenes were also obtained by reacting the dianion with corresponding alkane diselenocyanates. The thermal reaction of the 1,3-bis(alkylseleno)allenes mainly afforded enediynes through radical pathway, and the nine-membered cyclic allene provided intramolecular cyclization product via an intramolecular rearrangement. Heating of the cyclic bisallenes gave compounds derived from intramolecular cyclization products together with a small amount of the enediynes. Irradiation of allenes caused rearrangement of the selenenyl group to give alkynes, and the alkynes also reacted photochemically to yield the enediynes.
- Shimizu,Miyasaka,Kamigata
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p. 1787 - 1794
(2007/10/03)
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- Synthesis and thermal reaction of 1,3-bis(alkylseleno)allenes
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(Equation presented) Reactions of Ph2C3 dianion, prepared from 1,3-diphenylpropyne and n-butyllithium, with dimethyl diselenide and benzylselenocyanate yielded 1,3-bis(methylseleno)-1,3-diphenylpropadiene and 1,3-bis(benzylseleno)-1,
- Shimizu, Toshio,Miyasaka, Daisuke,Kamigata, Nobumasa
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p. 1923 - 1925
(2007/10/03)
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