- Fast cyclotrimerization of a wide range of isocyanates to isocyanurates over acid/base conjugates under bulk conditions
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An array of organic bases DMAP (4-dimethylaminopyridine), DBU (1, 8-diazabicyclo [5.4.0] undec-7-ene), TBD (1, 5, 7-triazabicyclo [4.4.0] dec-5-ene), and their base/acid conjugate organocatalyst systems were evaluated in the trimerization of various isocyanates. The performance depended greatly on the combination of the catalyst systems, and the [HTBD][OAc] (acetic acid) catalyst systems were considerably the most active in contrast to the corresponding DMAP and DBU counterparts. The [HTBD][OAc] catalyst system was capable of providing isocyanurates from the cyclotrimerization of various isocyanate substrates in excellent yields in seconds even under bulk conditions. A bifunctional catalytic mechanism over [HTBD][OAc] was proposed.
- Cheng, Ruihua,Liu, Wei,Wu, Li,Ye, Jinxing
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- Efficient and selective trimerization of aryl and alkyl isocyanates catalyzed by sodium p-toluenesulfinate in the presence of TBAI in a solvent-free condition
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Aryl and alkyl isocyanates have been efficiently converted into symmetrical trisubstituted aryl and alkyl isocyanurates, catalyzed by sodium p-toluenesulfinate on its own or in the presence of tetrabutylammonium iodide (TBAI), in a solvent-free condition.
- Moghaddam, Firouz Matloubi,Dekamin, Mohammad G.,Khajavi, Mohammad S.,Jalili, Seifollah
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- Macrocyclic complexes containing a platinacycle or palladacycle composed of an isocyanate dimer unit: Reactivity towards isocyanides and cyclotrimerization of isocyanates
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The reactions of [Pt(styrene)(PMe3)2] with 2 equiv. of alkyl or aryl isocyanate affored five-membered platinacycles, cis-[Pt{-N(R)C(O)N(R)C(O)-}(PMe3)2] (R = CH2C6H5, p-ClC6H4, p-OMeC6H4). These complexes are the first examples of platinacycles containing an isocyanate dimer unit. When the five-membered bis(phosphine) platinacycles or palladacycles were treated with 2 equiv. of elemental sulfur, 16-membered cyclic products as an assembly of four platinacycles or palladacycles, [M(PR3){-N(R)C(O)N(R)C(O)-}]4, were readily obtained. These cyclic tetramers were cleaved using tert-butyl isocyanide (CN-tbutyl, 4 equiv.), affording the corresponding monomeric complexes, [M(PR3)(CN-tbutyl){-N(R)C(O)N(R)C(O)-}] (M = Pt, Pd). An unusual cyclotrimerization of organic isocyanates catalyzed by zerovalent Pt complexes or five-membered platinacycles was observed. In addition, the direct cyclotrimerization of alkyl or aryl isocyanates using dialkyl Pt(II) or Pd(II) complexes was investigated. The cross cyclotrimerization of an aryl isocyanate and its derivative using a zerovalent Pd complex was also investigated.
- Choi, Jun-Hwan,Jung, Kang-Yeoun,Kim, Yong-Joo,Im, Hye Jin,Lee, Soon W.
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- Potassium complexes containing bidentate pyrrole ligands: Synthesis, structures, and catalytic activity for the cyclotrimerization of isocyanates
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Bidentate pyrrolyl ligands, 2-(t-butyliminomethyl)pyrrole and 2-(t-butylaminomethyl)pyrrole, reacted with KH to give complexes [C4H3N(2-CHNtBu)K(THF)]n (1) and [C4H3N(2-CH2NHsup
- Guo, Zhiqiang,Xu, Yuan,Wu, Xiaoqin,Wei, Xuehong,Xi, Chanjuan
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- Combination of sulfite anion and Phase Transfer Catalysts for green cyclotrimerization of aryl isocyanates
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The catalytic cyclotrimerization of aryl and alkyl isocyanates by the novel combination catalysts of sulfite ion and Phase Transfer Catalysts (PTCs), as selective anionic catalysts, has been investigated. The use of phase transfer catalyst features the ca
- Dekamin, Mohammad G.,Mallakpour, Shadpour,Ghassemi, Maryam
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- Lithium complex of 2-amino-functionalized benzoylpyrrole: Synthesis, structure, and catalytic activity for the cyclotrimerization of isocyanates
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Lithium complex stabilised by 2-amino-functionalized benzoylpyrrole was synthesized, and its structural features were provided. The molecular structure shows a novel tetrameric cage structure, which includes a eight-membered (LiN)4 ring and a e
- Guo, Zhiqiang,Wang, Yakong,Yang, Jihong,Wei, Xuehong
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Read Online
- Tridentate pyrrolylzinc compounds: Synthesis, structures, reactivities and catalytic cyclotrimerization reaction of isocyanate
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The reactions of ZnEt2 with NNN-tridentate pincer type pyrrolyl ligands, 2,5-bis((dimethylamino)methylene)-1H-pyrrole (HL1), 2,5-bis((pyrrolidin-1-yl)methylene)-1H-pyrrole (HL2) and 2,5-bis((piperidino)methylene)-1H-pyrrol
- Guo, Zhiqiang,Wei, Xuehong,Tong, Hongbo,Liu, Diansheng
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Read Online
- Synergistic Catalysis by Br?nsted Acid/Carbodicarbene Mimicking Frustrated Lewis Pair-Like Reactivity
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Carbodicarbene (CDC), unique carbenic entities bearing two lone pairs of electrons are well-known for their strong Lewis basicity. We demonstrate herein, upon introducing a weak Br?nsted acid benzyl alcohol (BnOH) as a co-modulator, CDC is remolded into a Frustrated Lewis Pair (FLP)-like reactivity. DFT calculation and experimental evidence show BnOH loosely interacting with the binding pocket of CDC via H-bonding and π-π stacking. Four distinct reactions in nature were deployed to demonstrate the viability of proof-of-concept as synergistic FLP/Modulator (CDC/BnOH), demonstrating enhanced catalytic reactivity in cyclotrimerization of isocyanate, polymerization process for L-lactide (LA), methyl methacrylate (MMA) and dehydrosilylation of alcohols. Importantly, the catalytic reactivity of carbodicarbene is uniquely distinct from conventional NHC which relies on only single chemical feature of nucleophilicity. This finding also provides a new spin in diversifying FLP reactivity with co-modulator or co-catalyst.
- Bai, Yuna,Chan, Yi-Chen,Chen, Hsing-Yin,Chen, Hsuan-Ying,Chen, Wen-Ching,Li, Chen-Yu,Ong, Tiow-Gan,Tseng, Mei-Chun,Wu, Ying-Yann,Yap, Glenn P. A.,Zhao, Lili
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supporting information
p. 19949 - 19956
(2021/08/03)
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- Yttrium dialkyl supported by a silaamidinate ligand: Synthesis, structure and catalysis on cyclotrimerization of isocyanates
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A sterically demanding silaamidine (ArN = Si(L)NHAr) ligand was synthesized and employed for the preparation of a yttrium dialkyl complex, which catalytically enabled the cyclotrimerization of isocyanate with high activity and excellent functional group t
- Liu, Deshuai,Zhou, Dahai,Yang, Hao,Li, Jianfeng,Cui, Chunming
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supporting information
p. 12324 - 12327
(2019/10/19)
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- Aluminium-catalysed isocyanate trimerization, enhanced by exploiting a dynamic coordination sphere
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Main-group metals are inherently labile, hindering their use in catalysis. We exploit this lability in the synthesis of isocyanurates. For the first time we report a highly active catalyst that trimerizes alkyl, allyl and aryl isocyanates, and di-isocyanates, with low catalyst loadings under mild conditions, using a hemi-labile aluminium-pyridyl-bis(iminophenolate) complex.
- Bahili, Mohammed A.,Stokes, Emily C.,Amesbury, Robert C.,Ould, Darren M. C.,Christo, Bashar,Horne, Rhian J.,Kariuki, Benson M.,Stewart, Jack A.,Taylor, Rebekah L.,Williams, P. Andrew,Jones, Matthew D.,Harris, Kenneth D. M.,Ward, Benjamin D.
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supporting information
p. 7679 - 7682
(2019/07/08)
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- Highly efficient cyclotrimerization of isocyanates using N-heterocyclic olefins under bulk conditions
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With a catalyst loading as low as 0.005%, high to excellent yields of isocyanurates could be achieved from N-heterocyclic olefin mediated organocatalytic cyclotrimerization of a wide range of isocyanates under bulk conditions. Experimental details coupled with structural characterization of the key intermediates led to comprehensive mechanistic studies of cyclotrimerization.
- Li, Chengkai,Zhao, Wuchao,He, Jianghua,Zhang, Yuetao
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supporting information
p. 12563 - 12566
(2019/10/28)
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- Isocyanurate Formation During Oxazolidinone Synthesis from Epoxides and Isocyanates Catalysed by a Chromium(Salphen) Complex
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Chromium(salphen) complex 10 is found to be a catalyst for the preparation of oxazolidinones from epoxides and isocyanates. Using the optimal reaction conditions (1.5 mol % of chromium(salphen) complex 10 at 80 °C in toluene for 4 hours), six epoxides wer
- Wu, Xiao,Mason, Jess,North, Michael
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p. 12937 - 12943
(2017/09/25)
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- Cyclic tetramers of a five-membered palladacycle based on a head-to-tail-linked isocyanate dimer and their reactivity in cyclotrimerization of isocyanates
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Reactions of [Pd(styrene)(PR3)2], generated from trans-[PdEt2(PR3)2] and styrene, with 2 equiv. of benzyl isocyanate in THF at room-temperature afforded unusual cyclic Pd-tetramers of five-membered rings consisting of organic isocyanate dimers and palladium, [Pd(PR3){-C(O)N(R)C(O)N(R)-}]4 (PR3 = PMe3, 1; PR3 = PMe2Ph, 2). Additionally, a cyclic trimer, (RNCO)3, 3 (R = benzyl) was produced as a catalytic product. Treatment of the cyclic tetramer (1) with 4 equiv. of chelated phosphine, such as (1,2-bis(diethylphosphino)ethane) (DEPE) or (1,2-bis(dimethylphosphino)ethane) (DMPE), readily caused conversion to a metallacyclic cis-form, [Pd{N(R)C(O)N(R)C(O)}(P ~ P)] (P ~ P = DEPE, 4; P ~ P = DMPE, 5) in quantitative yields. In contrast, reactions of Pd(0)-PR3 with 2 equiv. of Ar-NCO (Ar = Ph, p-tolyl, p-ClC6H4) afforded metallacyclic complexes having a dimeric isocyanato moiety, cis-[Pd{C(O)N(Ar)-C(O)N(Ar)}(PR3)2] (PR3 = PMe3 Ar = C6H5, 6; p-MeC6H4, 7; p-Cl-C6H4, 8; PR3 = PMe2Ph, Ar = p-Cl-C6H4, 9). Treatment of the palladacyclic complex (8) with an equimolar amount of chelated phosphine such as DEPE readily caused conversion to a palladacyclic cis-form, [Pd{N(Ar)C(O)N(Ar)C(O)}(DEPE)], 10 in quantitative yield. The catalytic cyclotrimerization of benzyl isocyanate to [Pd(styrene)(PMe3)2] was achieved by varying the molar ratio of R-NCO (R = benzyl). In addition, catalytic cyclotrimerization was performed from the five-membered palladacyclic complexes or the Pd(0)-PR3 complex with excess Ar-NCO. This journal is
- Lee, Seon Gye,Choi, Keun-Young,Kim, Yong-Joo,Park, Sujin,Lee, Soon W.
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p. 6537 - 6545
(2015/04/14)
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- Lithium, magnesium, zinc complexes supported by tridentate pincer type pyrrolyl ligands: Synthesis, crystal structures and catalytic activities for the cyclotrimerization of isocyanates
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Lithium, magnesium, zinc complexes incorporating substituted symmetrical tridentate pyrrolyl ligands were synthesized conveniently and their application for the cyclotrimerization of isocyanate to corresponding isocyanurate has been investigated. The reac
- Liu, Qiao,Guo, Zhiqiang,Han, Hongfei,Tong, Hongbo,Wei, Xuehong
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- Lithium, magnesium, zinc complexes supported by tridentate pincer type pyrrolyl ligands: Synthesis, crystal structures and catalytic activities for the cyclotrimerization of isocyanates
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Lithium, magnesium, zinc complexes incorporating substituted symmetrical tridentate pyrrolyl ligands were synthesized conveniently and their application for the cyclotrimerization of isocyanate to corresponding isocyanurate has been investigated. The reac
- Liu, Qiao,Guo, Zhiqiang,Han, Hongfei,Tong, Hongbo,Wei, Xuehong
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supporting information
p. 15 - 19
(2015/03/05)
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- An expeditious method for the selective cyclotrimerization of isocyanates initiated by TDAE
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We developed a rapid and green synthesis of various isocyanurates by cyclotrimerization of isocyanates using TDAE (tetrakis(dimethylamino)ethylene). TDAE displays excellent performance in catalytic quantities, affording the corresponding trimer of isocyanates very rapidly, under air and at room temperature in good to excellent yields.
- Giuglio-Tonolo, Alain G.,Spitz, Cédric,Terme, Thierry,Vanelle, Patrice
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p. 2700 - 2702
(2014/05/06)
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- Bidentate pyrrolyl lithium complexes: Synthesis, crystal structure and catalytic activity for the cyclotrimerization of isocyanates
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Three bidentate pyrrolyl lithium complexes were synthesized and their application for the cyclotrimerization of isocyanate to corresponding isocyanurate has been investigated and show high catalytic activities. All lithium complexes were characterized by
- Guo, Zhiqiang,Wang, Song,Tong, Hongbo,Chao, Jianbin,Wei, Xuehong
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- Developing catalytic applications of cooperative bimetallics: Competitive hydroamination/trimerization reactions of isocyanates catalysed by sodium magnesiates
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Mixed-metal reagents [NaMg(CH2SiMe3)3] (1) and [(THF)NaMg(NPh2)3(THF)] [3-(THF)2] can act as precatalysts to selectively promote the hydroamination/trimerization of isocyanates (RNCO) depen
- Hernan-Gomez, Alberto,Bradley, Tyne D.,Kennedy, Alan R.,Livingstone, Zoe,Robertson, Stuart D.,Hevia, Eva
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supporting information
p. 8659 - 8661
(2013/09/23)
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- Lithium dibenzylamide, a simple, selective and highly efficient catalyst for isocyanate cyclotrimerization to isocyanurate
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Lithium dibenzylamide catalyzed the rapid and essentially quantitative cyclotrimerization of a variety of isocyanates under mild conditions and could be recycled for six times in high yield. Georg Thieme Verlag Stuttgart New York.
- Shi, Jingchao,Guo, Zhiqiang,Wei, Xuehong,Liu, Diansheng,Lappert, Michael F.
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supporting information; scheme or table
p. 1937 - 1939
(2011/10/01)
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- Cyclodimerization and cyclotrimerization of isocyanates promoted by one praseodymium benzenethiolate complex [Pr(SPh)3(THF)3]
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The cyclotrimerization of aryl isocyanates and the cyclodimerization of alkyl isocyanates initiated by one praseodymium benzenethiolate complex [Pr(SPh)3(THF)3] were investigated. Comparative runs with [Pr(SPh)3(THF)3] and its precursor Pr[(Me 3Si)2N]3 showed that the former has the advantages of a higher selectivity toward isocyanates, easy preparation, low catalyst loading, high conversion as well as mild reaction conditions.
- Wang, He-Ming,Li, Hong-Xi,Yu, Xiang-Yang,Ren, Zhi-Gang,Lang, Jian-Ping
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experimental part
p. 1530 - 1535
(2011/04/15)
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- Organocatalytic, rapid and facile cyclotrimerization of isocyanates using tetrabutylammonium phthalimide-N-oxyl and tetraethylammonium 2-(carbamoyl)benzoate under solvent-free conditions
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Tetrabutylammonium phthalimide-N-oxyl and tetraethylammonium 2-(carbamoyl)benzoate were found to be effective and easily accessible organocatalysts for selective cylotrimerization of aryl and alkyl isocyanates under mild reaction conditions. The reaction proceeds smoothly using very low catalyst loadings of these metal-free organocatalysts (0.025 and 0.25 mol%, respectively) under solvent-free conditions at room temperature within a very short reaction time.
- Dekamin, Mohammad G.,Varmira, Kambiz,Farahmand, Mehdi,Sagheb-Asl, Solmaz,Karimi, Zahra
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experimental part
p. 226 - 230
(2011/09/14)
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- An electron-rich proazaphosphatrane for isocyanate trimerization to isocyanurates
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(Figure presented) A facile synthesis of the new electron-rich, sterically hindered proazaphosphatrane shown above is described herein. This proazaphosphatrane catalyzes the cyclotrimerization of a wide variety of isocyanates to isocyanurates under mild c
- Raders, Steven M.,Verkade, John G.
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experimental part
p. 5308 - 5311
(2010/10/19)
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- Polymer-supported, carbon dioxide-protected n-heterocyclic carbenes: Synthesis and application in organo- and organometallic catalysis
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The synthesis of a resin-supported, carbon dioxide-protected N-heterocyclic carbene (NHC) and its use in organocatalysis and organometallic catalysis are described. The resin-bound carbon dioxide-protected NHC-based catalyst was prepared via ring-opening
- Pawar, Gajanan Manohar,Buchmeiser, Michael R.
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scheme or table
p. 917 - 928
(2010/06/15)
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- CO2 and SnII adducts of N-heterocyclic carbenes as delayed-action catalysts for polyurethane synthesis
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A series of CO2-protected pyrimidin-2-ylidenes as well as 1,3-dimesitylimidazol-2-ylidene and dimesitylimidazolin-2-ylidene complexes of SnII have been prepared. Selected single-crystal X-ray structures are reported. The new compound
- Bantu, Bhasker,Pawar, Gajanan Manohar,Decker, Ulrich,Wurst, Klaus,Schmidt, Axel M.,Buchmeiser, Michael R.
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experimental part
p. 3103 - 3109
(2009/11/30)
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- The performance of phthalimide-N-oxyl anion
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Alkali metal salts of phthalimide-N-oxyl, including Li, Na, and K were prepared and applied as novel selective catalysts to promote the cyclotrimerization of aryl and alkyl isocyanates. This paper is addressing these salts as a new class of organic nucleo
- Dekamin, Mohammad G.,Moghaddam, Firouz M.,Saeidian, Hamdollah,Mallakpour, Shadpour
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p. 1591 - 1595
(2007/10/03)
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- Sulfate catalysed multicomponent cyclisation reaction of aryl isocyanates under green conditions
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Sulfate anion, as a novel anionic catalyst, promotes the multicomponent cyclisation of aryl isocyantes to give heterocyclic symmetrical isocyanurates selectively under solvent-free conditions. The use of phase transfer catalysts reduces reaction times by
- Dekamin, Mohammad G.,Mallakpour, Shadpour,Ghassemi, Maryam
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p. 177 - 179
(2007/10/03)
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- First synthesis of a highly basic dendrimer and its catalytic application in organic methodology
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Sixteen OCH2CH2N3P(i-BuNCH 2CH2)3N substituents (A) containing the highly basic bicyclic azido-phosphine moiety shown, have been incorporated into the dendrimer [CH2CH2/sub
- Sarkar, Arunkanti,Ilankumaran, Palanichamy,Kisanga, Philip,Verkade, John G.
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p. 1093 - 1096
(2007/10/03)
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- Solvent-free efficient synthesis of symmetrical isocyanurates by a combination catalyst: Sodium saccharin and tetrabutylammonium iodide
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Combination of sodium saccharin and tetrabutylammonium iodide as a novel anionic catalyst system promotes selectively the trimerization of isocyanates to give symmetrical isocyanurates under solvent-free conditions. Springer-Verlag 2004.
- Matloubi Moghaddam, Firouz,Koozehgiri, Gholam R.,Dekamin, Mohammad G.
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p. 849 - 851
(2007/10/03)
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- Haloamidation of alkynes and related reactions using zirconacycles and isocyanates
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Zirconacyclopentenes reacted with isocyanates to give aza- or oxazirconacycles which were conveniently coverted into the corresponding haloamidation products of alkynes after halogenation. 1,4-Bistrimethylsilyl substituted zirconacyclopentadiene afforded a low yield of iodoamidation product, whereas zirconium-alkyne complexes stabilized with phosphine gave the iodoamidation products in moderate yields. On the other hand, zirconacyclopentanes reacted with isocyanates to give trimerization products of isocyanate, isocyanurates.
- Li, Yanzhong,Matsumura, Hiroshi,Yamanaka, Masamichi,Takahashi, Tamotsu
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p. 1393 - 1400
(2007/10/03)
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- Solvent-free cyclotrimerization of isocyanates catalysed by sodium or potassium piperidinedithiocarbamate or nitrite under conventional or microwave heating: Preparation of aryl or alkyl isocyanurates
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A solvent-free method for the efficient preparation of symmetrically trisubstituted aryl or alkyl isocyanurates from isocyanates catalysed by sodium or potassium piperidinedithiocarbamate or the readily available sodium or potassium nitrite under conventi
- Khajavi, Mohammad S.,Dakamin, Mohammad G.,Hazarkhani, Hassan
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p. 145 - 147
(2007/10/03)
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- A new simple synthesis of 3,5-disubstituted 1-amino-1,3,5-triazine- 2,4,6-triones from ethoxycarbonylhydrazones and isocyanates
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The 3,5-disubstituted 1-amino-1,3,5,-triazine-2,4,6-triones were synthesized in good yields from aromatic aldehyde or ketone ethoxycarbonylhydrazones by treatment with aryl or methyl isocyanates in boiling triethylamine followed by hydrolysis with hydrochloric acid solution.
- Chau,Malanda,Milcent
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p. 261 - 263
(2007/10/03)
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- The Synthesis of Isocyanurates on the Trimerization of Isocyanates under High Pressure
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The trimerization of phenyl isocyanate in the presence of triethylamine was accelerated under high pressure to give triphenyl isocyanurates almost quantitatively.The reaction in benzen was remarkably accelerated by compression.The effects of pressure, temperature, catalysts, and solvents were examined on the trimerization of phenyl isocyanate.Aryl and normal alkyl isocyanates trimerized under high pressure to give the corresponding isocyanurates in good yields, whereas isocynates having bulky alkyl groups such as t-butyl and cyclohexyl did not trimerize even under 800 MPa.
- Taguchi, Yoichi,Shibuya, Isao,Yasumoto, Masahiko,Tsuchiya, Tohru,Yonemoto, Katsumi
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p. 3486 - 3489
(2007/10/02)
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- A Novel Spontaneous Alternating Copolymerization of Methoxyallene with 4-Chlorophenyl Isocyanate
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The spontaneous alternating copolymerization of methoxyallene with 4-chlorophenyl isocyanate proceeded through zwitterion to give polyamide having highly reactive exo-methylene groups bonded onto polymer backbone, accompanying the partial formation of β-l
- Mizuya, Jiro,Yokozawa, Tsutomu,Endo, Takeshi
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p. 479 - 480
(2007/10/02)
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