共查询到20条相似文献,搜索用时 150 毫秒
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1-苯基-1-烷基炔烃的炔丙位氢非常容易被碱攫取,得到炔丙基锂或联烯基锂中间体.之后,反应得到的中间体锂试剂通过与溴化锌发生交换,生成相应的有机锌试剂.在零价钯的作用下与PhI发生Negishi偶联,以较好的产率得到联烯.根据我们小组以往的工作,发现联烯锂与其异构体炔丙基锂之间存在平衡,而在这个反应中,我们只观察到联烯产物的生成,并没有炔的产生.但是,联烯产物之间却有一种异构存在.通过研究我们可以调整反应的选择性. 相似文献
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A new procedure for stereoselective synthesis of trisubstituted alkenes by an one-pot, three-component reaction of N-tosylated imines with α,β-acetylenic ketones and organozinc species CF3COOZnEt was described. This reaction system provides β-branched Morita–Baylis–Hillman adducts with excellent yields in absence of any catalyst. 相似文献
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An efficient procedure for preparation of α,β-dehydroamino acids from the reaction of acetylenic ketones with N-(diphenylmethylene)glycinates 2 is described. The reaction of terminal acetylenic ketones with 2 promoted by Et3N at −10 °C gave the dehydroamino acids containing ketone group in good yields. 相似文献
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Monosubstituted acetylenes were iodinated to form iodoacetylenes under simple conditions. Reaction of aryl acetylenes with molecular iodine in the presence of 4‐dimethylaminopyridine (DMAP) gave the desired products in good to excellent yields. Iodination of aryl acetylenic ketones using K2CO3 as base was also described. 相似文献
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A Ph3P‐catalyzed cyclization of α‐halogeno ketones 2 with dialkyl acetylenedicarboxylates (=dialkyl but‐2‐ynedioates) 3 produced halogenated α,β‐unsaturated γ‐butyrolactone derivatives 4 in good yields (Scheme 1, Table). The presence of electron‐withdrawing groups such as halogen atoms at the α‐position of the ketones was necessary in this reaction. Cyclization of α‐chloro ketones resulted in higher yields than that of the corresponding α‐bromo ketones. Dihalogeno ketones similarly afforded the expected γ‐butyrolactone derivatives in high yields. 相似文献
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An efficient cobalt‐catalyzed chemoselective reduction of β‐CF3‐α,β‐unsaturated ketones using benzylamine as hydrogen transfer agent involving intramolecular 1,5‐hydrogen transfer is reported. The reaction proceeded smoothly with a relatively wide range of substrates including those bearing aromatic heterocycles such as a furyl ring system in high yields (74–92 %). This provides an efficient method for the synthesis of β‐CF3 saturated ketones in one‐pot. This methodology was also applied to the selective C=C reduction of other enone substrates bearing no β‐CF3‐substituent, of which β‐substituted or β,β‐disubstituted enones are tolerated, giving the desired products in good yields (72–75 %). Mechanistic studies indicate that the reaction involves 1,5‐hydrogen transfer. 相似文献
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Palladium-catalyzed hydrostannylation of acetylenic sulfones 1 in benzene at room temperature gives highly regio- and stereoselectively (E)-α-stannylvinyl sulfones 2 in high yields. (E)-α-Stannylvinyl sulfones 2 are new difunctional group reagents which undergo Stille coupling reactions with acyl chlorides 3 to afford stereoselectively (Z)-α-arylsulfonyl-α,β-unsaturated ketones 4 in good yields. A one-pot stereoselective synthesis of (Z)-α-arylsulfonyl-α,β-unsaturated ketones 4 has also been achieved by tandem hydrostannylation-Stille coupling reaction of acetylenic sulfones 1 under mild conditions. 相似文献
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Chan Sik Cho 《Journal of organometallic chemistry》2005,690(17):4094-4097
2-Iodoaniline reacts with terminal acetylenic carbinols in THF at 80 °C in the presence of a catalytic amount of PdCl2(PPh3)2 and CuI along with aqueous tetrabutylammonium hydroxide to afford the corresponding 2-arylquinolines in good yields. The catalytic pathway seems to be proceeded via a sequence involving initial Sonogashira coupling between 2-iodoaniline and terminal acetylenic carbinols to form coupled acetylenic carbinols, isomerization of coupled acetylenic carbinols to α,β-unsaturated ketones, and cyclodehydration. 相似文献
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Zolfigol Mohammad Ali Khazaei Ardeshir Mokhlesi Mohammad Zare Abdolkarim Safaiee Maliheh Derakhshan‐Panah Fatemeh Keypour Hassan Ali Dehghani‐Firouzabadi Ahmad Merajoddin Maria 《中国化学》2012,30(2):345-352
Aluminum chloride (AlCl3) efficiently catalyzes one‐pot multicomponent condensation of enolizable ketones or alkyl acetoacetates with aldehydes, acetonitrile and acetyl chloride to afford β‐acetamido ketone or ester derivatives in high to excellent yields and in relatively short reaction times. Moreover, by this synthetic method, some novel β‐acetamido ketones and esters (i.e. one complex structure) are prepared. 相似文献
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Tadashi Narita 《Macromolecular rapid communications》2000,21(10):613-627
The polymerization reactivities of α,β,β‐trifluorovinyl compounds (CF2=CF—R) and α‐trifluoromethylvinyl compounds (CH2=C(CF3)—R) are discussed since these monomers have scarcely been investigated and hardly yielded corresponding homopolymers, although tetrafluoroethylene and chlorotrifluoroethylene have been studied under radical polymerization conditions. In the case of α,β,β‐trifluorostyrene, a homopolymer is obtained in low yields by anionic polymerization and it is concluded that the reaction takes place without any side reactions once the reaction has started, since simple addition polymerization is observed and the molecular weight distribution is very narrow. Anionic polymerization of hexafluorobuta‐1,3‐diene is successfully achieved by the addition reaction of living end to the 2‐carbon of hexafluorobuta‐1,3‐diene followed by isomerization to produce excellently high thermostable polymers. ω‐Trifluorovinyloxyfluoroalkyl alcohol produces a polyether via a polyaddition reaction under anionic conditions. The homopolymers of α‐trifluoromethylacrylates are quantitatively obtained under anionic polymerization conditions. α‐Trifluoromethylstyrene derivatives are likely to polymerize under radical conditions, but are not well‐studied. The radical polyaddition reaction of perfluoroisopropenyl esters in 1,4‐dioxane, diethyl ether or 1,2‐dimethoxyethane yields the polymers possessing the solvent moiety in the polymer main chain, respectively. It is clearly demonstrated that each fluorinated vinyl monomer discussed in this article demands its own reaction conditions. Therefore, more experimental data on the polymerization of these individual monomers is needed, including research on developing the reactions discovered in the organofluorine chemistry field to the preparation of polymers. 相似文献
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Kazuyuki Sato 《Tetrahedron letters》2008,49(22):3558-3561
The treatment of silyl enol ethers of ketones with CF3-I and Et2Zn in the presence of RhCl(PPh3)3 in DME gave α-trifluoromethyl ketones in good yields. The reaction can be widely applicable to silyl enol ethers derived from aliphatic or aromatic ketones. In the absence of the rhodium catalyst, the reaction was very slow and the yields were quite poor. 相似文献