10099-70-4Relevant articles and documents
Donor-Acceptor Fluorophores for Energy-Transfer-Mediated Photocatalysis
Lu, Jingzhi,Pattengale, Brian,Liu, Qiuhua,Yang, Sizhuo,Li, Shuzhou,Huang, Jier,Zhang, Jian
supporting information, p. 13719 - 13725 (2018/10/24)
Triplet-triplet energy transfer (EnT) is a fundamental activation pathway in photocatalysis. In this work, we report the mechanistic origins of the triplet excited state of carbazole-cyanobenzene donor-acceptor (D-A) fluorophores in EnT-based photocatalytic reactions and demonstrate the key factors that control the accessibility of the 3LE (locally excited triplet state) and 3CT (charge-transfer triplet state) via a combined photochemical and transient absorption spectroscopic study. We found that the energy order between 1CT (charge transfer singlet state) and 3LE dictates the accessibility of 3LE/3CT for EnT, which can be effectively engineered by varying solvent polarity and D-A character to depopulate 3LE and facilitate EnT from the chemically more tunable 3CT state for photosensitization. Following the above design principle, a new D-A fluorophore with strong D-A character and weak redox potential is identified, which exhibits high efficiency for Ni(II)-catalyzed cross-coupling of carboxylic acids and aryl halides with a wide substrate scope and high selectivity. Our results not only provide key fundamental insight on the EnT mechanism of D-A fluorophores but also establish its wide utility in EnT-mediated photocatalytic reactions.
Photoorganocatalytic synthesis of lactones: Via a selective C-H activation-alkylation of alcohols
Kaplaneris, Nikolaos,Bisticha, Aikaterini,Papadopoulos, Giorgos N.,Limnios, Dimitris,Kokotos, Christoforos G.
supporting information, p. 4451 - 4456 (2017/09/29)
Selective C-H activation is an area of growing importance in modern organic chemistry. Herein, we report our efforts in combining organocatalysis and photocatalysis for the development of a highly efficient and selective visible-light mediated protocol for the C-H activation and addition of various alcohols to a plethora of Michael acceptors, followed by a cyclization reaction leading to lactones, a repeatedly occurring motif in nature. Utilizing phenylglyoxylic acid as the photocatalyst and common household bulbs as the light source, we describe a versatile α-alkylation/lactonization of alcohols with α,β-unsaturated esters leading to products in excellent yields. The reaction mechanism was extensively studied.
Efficient synthesis of symmetrical phthalate and maleate diesters using phosphinite ionic liquids
Valizadeh,Khalili
, p. 529 - 534 (2013/02/22)
Symmetrical dialkyl phthalates and maleates were synthesized using phosphinite ionic liquid as a catalyst and reaction medium. The results indicated that phosphinite ionic liquid shows better catalytic and reusable performance without using any acid or base catalyst. Under the optimum conditions, using 1-methyl-3-(4-phosphinitebutyl) imidazolium chloride as catalyst, the conversion of phthalic and maleic anhydrides to the corresponding diesters of primary and secondary alcohols was occurred in 72-85% yields. The diesters of tertiary alcohols and phenols could not be prepared by this method. A kind of widely used plasticizer, dioctyl phthalate, was prepared in good yield under these conditions. The ionic liquid could be reused three times after easy separation from the products without any disposal. Iranian Chemical Society 2012.
Highly chemo- and stereoselective intermolecular coupling of diazoacetates to give cis-olefins by using Grubbs second-generation catalyst
Hodgson, David M.,Angrish, Deepshikha
, p. 3470 - 3479 (2008/02/08)
Highly stereoselective formation of cis-2-ene-1,4-diesters by homo- and heterocoupling of α-diazoacetates in the presence of Grubbs second-generation catalyst is demonstrated. The dual reactivity of the catalyst in alkene metathesis and diazocoupling has been exploited in the synthesis of 12-26-membered macrocyclic dienyl dilactones by one-pot carbene dimerisation/ring-closing metathesis.
Straightforward access to enantiomerically pure, highly functionalized pyrrolizidines by cycloaddition of maleic acid esters to pyrroline N-oxides derived from tartaric, malic and aspartic acids - Synthesis of (-)-hastanecine, 7-epi-croalbinecine and (-)-croalbinecine
Goti, Andrea,Cicchi, Stefano,Cacciarini, Martina,Cardona, Francesca,Fedi, Valentina,Brandi, Alberto
, p. 3633 - 3645 (2007/10/03)
The cycloaddition reactions of dimethyl maleate to three functionalized enantiopure pyrroline N-oxides and one related racemic nitrone are reported. The study of the diastereoselectivity in the cycloaddition has been carried out by ample variation of the substituents at both the dipole and dipolarophile counterparts. The major cycloadducts, derived from the preferred exo-anti transition states and formed with 62-90% diastereoselectivity, have been subjected to Mo(CO)6-induced reductive ring-opening to afford directly highly functionalized enantiopure pyrrolizinone derivatives, valuable as synthetic intermediates. Applications of this strategy to a straightforward formal synthesis of (-)-hastanecine and to the total synthesis of the novel 7-epi-croalbinecine and of (-)-croalbinecine are reported.
Unsaturated mono-esters and their use in coating compositions
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, (2008/06/13)
Hydroxy functional, unsaturated diesters are disclosed that comprise the esterification reaction products of unsaturated anhydrides with secondary alcohols to form monoesters, followed by oxyalkylation of the monoester with epoxy compounds, whereby a diester is formed with hydroxy functionality. Use of secondary alcohol yields monoesters less prone to disproportionation. The unsaturated diesters may be copolymerized with vinyl monomers to form hydroxy functional copolymers useful in coating applications, wherein they may be included in compositions along with a curing agent that is reactive with hydroxy groups.
Reactions of Wittig Reagents with Episulfides or Elemental Sulfur
Okuma, Kentaro,Tachibana, Yuji,Sakata, Jun-ichi,Komiya, Takashi,Kaneko, Isao,et al.
, p. 4323 - 4328 (2007/10/02)
The reactions of Wittig reagents with episulfides gave symmetrical olefins and triphenylphosphine sulfide in moderate yields.The same olefins were obtained by reactions of Wittig reagents with elementar sulfur.These reactions might proceed through thiocarbonyl intermediates, the existence of which was confirmed by Diels-Alder reactions with dienes.
Process for the preparation of Diels-Alder adducts of halogenated cyclopentadienes
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, (2008/06/13)
An improved process for the preparation of solid Diels-Alder adducts of halogenated cyclopentadienes and mono- or diolefins is disclosed wherein the reactants are combined in an aqueous emulsion. The adducts are obtained in excellent yield and in an extremely fine particulate form. The new process avoids the use of organic solvents which are relatively costly, hazardous to use, and from which the adducts are usually obtained as relatively large crystals which require pulverization prior to use.
