- Gold(I)-catalyzed tandem oxidative ring-opening/C-C bond cleavage reactions of vinylidenecyclopropanes with secondary amines under an oxygen atmosphere
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A Midas touch! Gold(I)-catalyzed tandem oxidative ring-opening/C-C bond cleavage reactions of vinylidenecyclopropanes with a variety of secondary amines proceeded smoothly in toluene or 1,1,2,2-tetrachloroethane (TCE) to give the corresponding amides in moderate to good yields under oxygen atmosphere (see scheme; DCE=1,2-dichloroethane). The scope and limitations as well as the plausible mechanisms have been discussed.
- Lu, Bei-Li,Shi, Min
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supporting information; experimental part
p. 9070 - 9075
(2011/09/19)
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- Lewis-acid-catalyzed rearrangement of arylvinylidenecyclopropanes: Significant influence of substituents and electronic nature of aryl groups
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Lewis-acid-catalyzed reactions of arylvinylidenecyclopropanes having three substituents at the corresponding cyclopropyl rings have been investigated thoroughly. The reaction products are highly dependent on the substituents at the corresponding cyclopropyl rings and the electronic nature of the aryl groups. For arylvinylidenecyclopropanes bearing two alkyl groups at the C-1 position (R1, R2, R3 = aryl; R4 = H; R5, R6 = alkyl), naphthalene derivatives were formed in the presence of Lewis-acid Eu(OTf)3 in DCE at 40 °C. For arylvinylidenecyclopropanes in which R1, R2, R3 = aryl and R4, R5 = alkyl (syn/anti isomeric mixtures), the corresponding 6aH-benzo[c]fluorine derivatives were formed in the syn-configuration via a double intramolecular Friedel-Crafts reaction when all of the aryl groups do not have electron-withdrawing groups or the corresponding indene derivatives were obtained via an intramolecular Friedel-Crafts reaction as long as one electron-deficient aryl group was attached. For arylvinylidenecyclopropanes in which R1, R2, R 3, R4 = aryl and R5 = alkyl or H, the corresponding indene derivatives were obtained exclusively via a sterically demanding intramolecular Friedel-Crafts reaction. Lewis-acid effects and mechanistic insights have been discussed on the basis of experimental investigations.
- Zhang, Yun-Peng,Lu, Jian-Mei,Xu, Guang-Cai,Shi, Min
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p. 509 - 516
(2007/10/03)
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- General and Convenient Route to Alkenylidenecyclopropanes: Generation of Alkenylidenecarbenes from 1,1-Dibromocyclopropanes under Phase-transfer Conditions
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Alkenylidenecyclopropanes have been prepared in a stereospecific manner by the reaction of 1,1-disubstituted 2,2-dibromocyclopropanes with sodium hydroxide under phase-transfer conditions in the presence of alkenes.
- Isagawa, Kakuzo,Mizuno, Kazuhiko,Sugita, Hikaru,Otsuji, Yoshio
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p. 2283 - 2285
(2007/10/02)
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