- SnCl2-catalyzed synthesis of carbamates from renewable origin alcohols
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Effects of structure and reactivity of renewable origin alcohols in the conversion and selectivity of the SnCl2-catalyzed reactions in the presence and absence of urea were assessed. Convenient simple and suitable method for the synthesis of carbamates from renewable origin alcohols and urea in one-step are provided. We have assessed the activity of SnCl2 catalyst, a commercially affordable Lewis acid, in reactions of urea alcoholysis with different natural origin alcohols (geranyl, neryl, bornyl, cinnamyl, α-terpinyl and benzyl alcohols), aiming to synthesize carbamates, which are biologically active compounds, building blocks in organic synthesis and raw material to synthesize polyurethanes. The low cost of urea, the water tolerant catalyst and phosgene free reaction are positive aspects of this carbamates synthesis process. The different reaction pathways were assessed. A mechanism was proposed based on FT-IR experiments and experimental data.
- da Silva, Márcio José,Chaves, Diego Morais
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- Indium(III)-Catalyzed Synthesis of Primary Carbamates and N-Substituted Ureas
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An indium triflate-catalyzed synthesis of primary carbamates from alcohols and urea as an ecofriendly carbonyl source has been developed. Various linear, branched, and cyclic alcohols were converted into the corresponding carbamates in good to excellent yields. This method also provided access to N-substituted ureas by carbamoylation of amines. All the products were obtained by simple filtration or crystallization, without the need for chromatographic purification. Mechanistic investigations suggest that the carbamoylation reaction proceeds through activation of urea by O-coordination with indium, followed by nucleophilic attack by the alcohol or amine on the carbonyl center of urea. The inexpensive and easily available starting materials and catalyst, the short reaction times, and the ease of product isolation highlight the inherent practicality of the developed method.
- Jain, Isha,Malik, Payal
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supporting information
p. 93 - 97
(2021/11/26)
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- Microwave-Assisted 1,3-Dioxa-[3,3]-Sigmatropic Rearrangement of Substituted Allylic Carbamates: Application to the Synthesis of Novel 1,3-Oxazine-2,4-dione Derivatives
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In a first instance, the effect of the microwave irradiation on the 1,3-Dioxa-[3,3]-sigmatropic rearrangement of aryl allylic carbamates was investigated. Under these new conditions, the reaction acceleration was clearly highlighted compared to convention
- Bou Zeid, Samar,Eid, Samar,Najjar, Fadia,Macé, Aurélie,Rivilla, Ivan,Cossío, Fernando P.,Dorcet, Vincent,Roisnel, Thierry,Carreaux, Fran?ois
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- Further development of the tin-catalyzed transcarbamoylation reaction
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Studies carried out to further develop tin-catalyzed trans-carbamoylation reactions demonstrated that transcarbamoylation of cinnamyl alcohol in the context of allyl cyanate-to-isocyanate rearrangement can be efficiently carried out on a ten-gram scale and that tin-catalyzed transcarbamoylation is a valuable alternative to the method using trichloroacetyl isocyanate. In addition, methyl carbamate was found to be an economical carabamoyl donor in tin-catalyzed transcarbamoylation, which showed broad functional group tolerance and allowed a streamlined workup procedure. Finally, a unique synthetic method was developed for the preparation of carbamate-tethered terpene glycoconjugates.
- Hasegawa, Tomoyuki,Ichikawa, Yoshiyasu,Masuda, Toshiya,Minami, Takahiro,Morishita, Yukinori,Ochi, Rika,Sato, Hiroshi
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p. 2373 - 2378
(2020/08/19)
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- 1,3-Dioxa-[3,3]-sigmatropic Oxo-Rearrangement of Substituted Allylic Carbamates: Scope and Mechanistic Studies
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An unexpected 1,3-dioxa-[3,3]-sigmatropic rearrangement during the treatment of aryl- and alkenyl-substituted allylic alcohols with activated isocyanates is reported. The reorganization of bonds is highly dependent on the electron density of the aromatic
- Agirre, Maddalen,Henrion, Sylvain,Rivilla, Ivan,Miranda, José I.,Cossío, Fernando P.,Carboni, Bertrand,Villalgordo, José M.,Carreaux, Fran?ois
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p. 14861 - 14881
(2019/01/04)
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- Iron-catalyzed reaction of urea with alcohols and amines: A safe alternative for the synthesis of primary carbamates
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A general study of the iron-catalyzed reaction of urea with nucleophiles is here presented. The carbamoylation of alcohols allows for the synthesis of N-unsubstituted (primary) carbamates, including present drugs (Felbamate and Meprobamat, without the necessity to apply phosgene and related derivatives. Using amines as nucleophiles gave rise to the respective mono-and disubstituted ureas via selective transamidation reaction. These atom-economical transformations provide a direct and selective access to valuable compounds from cheap and readily available urea using a simple Lewis-acidic iron(Icatalyst.
- Pe?a-López, Miguel,Neumann, Helfried,Beller, Matthias
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p. 2233 - 2238
(2017/07/25)
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- Substrate scope and stereocontrol in the Rh(II)-catalysed oxyamination of allylic carbamates
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Application of a modified Du Bois protocol for rhodium-stabilised nitrenoid generation to a variety of allylic carbamates results in 4-acetoxymethyl-1,3-oxazolidin-2-one derivatives with moderate to high levels of stereocontrol.
- Unsworth, William P.,Lamont, Scott G.,Robertson, Jeremy
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p. 7388 - 7394
(2017/09/12)
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- Iron(II)-catalyzed intramolecular aminohydroxylation of olefins with functionalized hydroxylamines
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A diastereoselective aminohydroxylation of olefins with a functionalized hydroxylamine is catalyzed by new iron(II) complexes. This efficient intramolecular process readily affords synthetically useful amino alcohols with excellent selectivity (dr up to > 20:1). Asymmetric catalysis with chiral iron(II) complexes and preliminary mechanistic studies reveal an iron nitrenoid is a possible intermediate that can undergo either aminohydroxylation or aziridination, and the selectivity can be controlled by careful selection of counteranion/ligand combinations.
- Liu, Guan-Sai,Zhang, Yong-Qiang,Yuan, Yong-An,Xu, Hao
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supporting information
p. 3343 - 3346
(2013/04/23)
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- Intramolecular iron(ii)-catalyzed aminobromination of allyl N-tosyloxycarbamates
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Allyl N-tosyloxycarbamates are found to be catalytically transformed into β-brominated oxazolidinones with FeBr2/n-Bu4NBr in t-BuOH. The Royal Society of Chemistry 2012.
- Kamon, Takuma,Shigeoka, Daisuke,Tanaka, Tetsuaki,Yoshimitsu, Takehiko
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body text
p. 2363 - 2365
(2012/04/11)
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- Metal-free intramolecular aziridination of allylic carbamates mediated by hypervalent iodine compounds
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An efficient and practical hypervalent iodine compound mediated metal-free intramolecular aziridination reaction of allylic carbamates was developed. Analytically pure aziridines were obtained in high yields by simple filtration of the reaction mixture. I
- Deng, Qing-Hai,Wang, Jing-Cui,Xu, Zhen-Jiang,Zhou, Cong-Ying,Che, Chi-Ming
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p. 2959 - 2967
(2011/10/19)
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- An efficient synthesis of carbamates by tin-catalyzed transcarbamoylation reactions of primary and secondary alcohols
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A new approach to the synthesis of carbamates based on a tin-catalyzed transcarbamoylation process has been developed. Reactions of primary and secondary alcohols with phenyl carbamate in toluene at 90 ° C proceed smoothly in the presence of tin-catalyst to generate the corresponding carbamates in good yields. This mild method exhibits a broad functional-group tolerance. Georg Thieme Verlag Stuttgart.
- Ichikawa, Yoshiyasu,Morishita, Yukinori,Kusaba, Shuhei,Sakiyama, Naoto,Matsuda, Yasunori,Nakano, Keiji,Kotsuki, Hiyoshizo
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experimental part
p. 1815 - 1818
(2010/10/05)
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- Complementary reactions of allylic carbamates using palladium(II): Formation of oxazolidinones or allylic amides from a common precursor
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The use of palladium to effect two different reactions on a common starting material is presented. With a copper oxidant, an aminohalogenation is achieved to produce oxazolidinones. When the copper is absent, a [3,3]-sigmatropic rearrangement takes place
- Christie, Steven D. R.,Warrington, Adam D.,Lunniss, Christopher J.
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experimental part
p. 148 - 154
(2009/06/18)
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- Tethered aminohydroxylation: Dramatic improvements to the process
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Changing the identity of the N leaving group on a hydroxylamine-based reoxidant gives a dramatic improvement to the tethered aminohydroxylation reaction. Using OCOC6F5 as a leaving group means that only 1 mol % of osmium is required and yields as high as 98% can be obtained. Acyclic homoallylic alcohols were substrates considered too unreactive for effective use in the tethered aminohydroxylation reaction; improved reaction conditions mean that they have now become viable substrates for oxidation.
- Donohoe, Timothy J.,Bataille, Carole J. R.,Gattrell, William,Kloesges, Johannes,Rossignol, Emilie
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p. 1725 - 1728
(2008/02/02)
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- Study of the stability of carbocations by chlorosulfonyl isocyanate reaction with ethers
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The stability order of various alkyl, allyl, and benzyl carbocations was investigated using the novel technique for comparing the stability of carbocations in solution developed by using a simple CSI reaction with various ethers. The p-methoxycinnamyl carbocation was the most stable in our reaction system and the next stable carbocation was the p-methoxybenzyl carbocation. The stability of the other carbocations decreased with methacryl, t-butyl, cinnamyl, acryl, benzyl, 2° and allyl carbocations in that order.
- Kim, Ji Duck,Han, Gyoonhee,Jeong, Lak Shin,Park, Hyun-Ju,Zee, Ok Pyo,Jung, Young Hoon
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p. 4395 - 4402
(2007/10/03)
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- A new synthetic method for the preparation of amino sugars through an allyl cyanate-to-isocyanate rearrangement
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A new approach for the synthesis of amino sugars using an allyl cyanate-to-isocyanate rearrangement has been developed. The key feature in this method involves introduction of the nitrogen substituent into the pyranose framework by [3,3] sigmatropic rearrangement of an allyl cyanate. Subsequent functionalization of the allylamine moiety by either hydroxylation or cyclofunctionalization completes the synthesis of two amino sugars, D-perosamine and D-vicenisamine.
- Ichikawa, Yoshiyasu,Osada, Masafumi,Ohtani, Ikuko I.,Isobe, Minoru
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p. 1449 - 1455
(2007/10/03)
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- Novel, Regioselective Allylamine Construction; First Synthesis of Geranyllinaloisocyanide, a Diterpene from the Marine Sponge, Halichondria Sp.
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The first synthesis of the diterpene, 3-isocyano-3,7,11,15-tetramethylhexadeca-1,6,10,14-tetraene (geranyllinaloisocyanide, 1), has been achieved through an allyl cyanate-to-isocyanate rearrangement.The crucial step in this synthesis is in situ transformation of allyl isocyanates into stable allyl acetamides with trimethylaluminium.
- Ichikawa, Yoshiyasu,Yamazaki, Masatugu,Isobe, Minoru
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p. 2429 - 2432
(2007/10/02)
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