Reactions of (+)-Camphene with Dithiols (original) (raw)
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Angewandte Chemie International Edition, 2006
1 Hand 13 C-NMR spectra were obtained on JEOL GSX-270 or JNM-AL400 spectrometers at 270 or 400 MHz in CDCl 3 with TMS as an internal standard. Infrared spectra were obtained with a JASCO FTIR-410. Analytical GLC and GLC-Mass were performed by Shimadzu GC-8A PF with flame ionization detector equipped with KOCL 3000T, Silicon SE-30, and OV-17 columns. JEOL JMS-700 mass spectrometer was used for HRMS analyses. Powder X-ray diffraction patterns were recorded using Philips X'Pert-MPD with Cu Kα radiation. NH 3-TPD of the samples was carried out in a flow-type fixed bed reactor using Japan BEL TPD-77 instrument. Material. Unless otherwise noted, materials were purchased from Wako Pure Chemicals, Tokyo Kasei Co., Nacalai tesque, and Aldrich Inc. and were used after appropriate purification. Solid Acids. Na +-montmorillonite (Na-mont), Na 0.66 (OH) 4 Si 8 (Al 3.34 Mg 0.66 Fe 0.19)O 20 , was purchased from Kunimine Industry Co. Ltd., JAPAN as Kunipia F. H-USY (N. E. Chemcat. Si/Al=10), H-ZSM-5 (JRC-Z5-25H), and H-Mordenite (JRC-Z-HM20) were used. SO 4 2-/ZrO 2 and mont K-10 were obtained from Wako Pure Chemicals and Aldrich Inc..
On the role of electronic and steric factors upon the formation of Meisenheimer-type adducts
J Org Chem, 1976
A 58/42 mixture of 6a and 7a (0.500 g), prepared through the sequence described above from the mixture of 2a and 3a obtained in the bromination of l a in ccl4 at 0 OC, was subjected to preparative TLC, a 7:3 mixture of ethyl acetate and hexane being used as the eluent. Elution was repeated three times. Extraction of the two bands (the faster moving band contains 7a) yielded 7a (0.070 g), mp 161.5-162 OC, and pure 6a as an oil (0.110 9).
Conjugate addition between syringol and a captodative olefin catalyzed by BF3
Journal of Physical Organic Chemistry, 2019
The regioselectivity of the conjugate addition between syringol (1) and the captodative olefin 3-(p-nitrobenzoyloxy)-but-3-en-2-one (2) is evaluated under diverse solvent and Lewis acid catalyst conditions, providing a mixture of the para/meta phenol adducts. Experimental results revealed for most of the trials that the para regioisomer is the major one. However, there is not a clear correlation between the regioselectivity of products and the polarity of the tested solvents. In this work, the reactivity descriptors and the reaction mechanism are studied in the framework of the density functional theory (DFT) to give insights about the reactivity and regioselectivity of this reaction. The Parr functions difference is used as the reactivity descriptor in each stage of the reaction explaining quite well the involved transition states. Overall, it is found that the reactivity of 1 is strongly influenced by the presence of the catalyst, while the regioselectivity of the products depends on both the catalyst and the polarity of the solvent, finding that, the meta adduct is highly dependent of the presence of nonpolar solvents.
Polyhedron, 2017
The reaction of the N,N-spiro bridged octachlorobis(cyclotriphosphazene), {N 3 P 3 Cl 4 [br-N (CH 2) 5 CH 3 ] 2 N 3 P 3 Cl 4 } (1), in three stoichiometries (1:0.7, 1:2 and 1:4) with the disodium salt of 1,3propanediol in THF at room temperature produced seven products, whose structures have been characterized by elemental analysis, mass spectrometry, 1 H and 31 P NMR spectroscopy; also the crystal structures of 6 and 8 were determined by X-ray crystallography. The reactions gave a mixture of rearranged derivatives (2, 4 and 5) in which the central four membered cyclophosphazane ring transformed into a six-membered monocyclophosphazene ring, as well as the normal substituted derivatives (3, 6-8). In addition, the results of all the reactions were compared with previous work on the reactions of the starting compound 1 with the disodium derivative of 1,2-ethanediol, in the same mole ratios and in the same solvent, THF.
Journal of Organic Chemistry, 2008
Baylis-Hillman adduct underwent smooth radical-induced condensation with activated bromo compounds and epoxides using titanocene(III) chloride (Cp 2 TiCl) as the radical generator. The reactions of activated bromo compounds with 3-acetoxy-2-methylene alkanoates provided (E)-alkenes exclusively, whereas similar reactions with 3-acetoxy-2-methylenealkanenitriles led to (Z)-alkenes as the major product. The reactions of epoxides with Baylis-Hillman adduct furnished R-methylene/arylidene-δ-lactones in good yield via addition followed by in situ lactonization. Acetates of Baylis-Hillman adduct have been established for stereoselective synthesis of different multifunctional molecules. 1 Moreover, the substituted alkene moiety is a part of varieties of naturally occurring bioactive molecules along with several important pheromones and antibiotics and also the key intermediate in the stereospecific synthesis of important compounds. 2 Various R-substituted acrylate esters have been extensively used in the synthesis of pseodopeptides, including inhibitors of metalloproteases and ATP-dependent ligases based on the 1,4-addition reaction. 3 Several methods are reported in the literature for the synthesis of substituted alkenes from Baylis-Hillman adducts such as Pd-catalyzed cross-coupling reaction, 4 reaction with Grignard reagent, 5 Friedel-Crafts reaction, 6 and more recently reaction of trialkylindium reagent. 7 Earlier, Das et al. have a considerable amount of contribution in the synthesis of alkenes from Baylis-Hillman adducts. 8 They have also developed a very elegant and high-yielding similar transformation using Zn in aqueous medium where both 10.
Journal of the Brazilian Chemical Society, 2010
Apresentamos aqui nossos resultados da adição de tióis, catalisada por PhSeBr, a compostos carbonílicos α,β-insaturados sob condições brandas para obter regiosseletivamente β-mercapto cetonas ou tioacetais com altos rendimentos e seletividade. A reação foi principalmente controlada pela temperatura, na qual os produtos de adição 1,4 foram obtidos à temperatura de -20 o C. Inversamente quando a reação foi realizada sob refluxo, tioacetais foram obtidos como único produto. O método admite diversos grupos funcionais, como alquilicos, benzilicos e arilicos com substituintes neutros, deficientes e ricos em elétrons no anel aromático.
Journal of the Brazilian Chemical Society, 2009
A reação do ligante ambidentado dibenzilsulfóxido (dbso) com Me 2 SnCl 2 na proporção molar 1:1 leva à formação do produto pentacoordenado [Me 2 SnCl 2 (dbso)], enquanto Ph 2 SnCl 2 leva à formação do complexo hexacoordenado trans-[Ph 2 SnCl 2 (dbso) 2 ], utilizando as mesmas condições de reação. Por outro lado, a reação com n Bu 2 SnCl 2 forma o produto bimetálico [{ n Bu 2 SnCl 2 (dbso)} 2 ], o qual provavelmente possui núcleos de estanho(IV) octaédricos e cloretos em ponte. Os complexos [MeSnCl 3 (dbso) 2 ] e [Ph 3 SnCl(dbso)] também foram preparados. Todos os produtos foram estudados por análise elementar e por espectroscopias no IV, RMN (1 H, 13 C, 119 Sn) e Mössbauer. As espécies hexacoordenadas fac-[MeSnCl 3 (dbso) 2 ] e trans-[Ph 2 SnCl 2 (dbso) 2 ] foram também estudadas por difratometria de raios X; as determinações estruturais revelaram que estes compostos cristalizam-se nos sistemas cristalinos ortorrômbico, Pbcn, e monoclínico, P2 1 /c, respectivamente. As moléculas possuem átomos de estanho(IV) numa geometria octaédrica distorcida, com os dois ligantes dbso em posições cis e trans, respectivamente. The reaction of the ambidentate ligand dibenzylsulfoxide (dbso) with Me 2 SnCl 2 in 1:1 molar ratio leads to the formation of the five-coordinate adduct [Me 2 SnCl 2 (dbso)], whereas the same reaction conditions with Ph 2 SnCl 2 provide the six-coordinate adduct trans-[Ph 2 SnCl 2 (dbso) 2 ]. On the other hand, the reaction with n Bu 2 SnCl 2 forms the dimeric adduct [{ n Bu 2 SnCl 2 (dbso)} 2 ], which probably possesses octahedral tin(IV) nuclei and bridging chlorides. The adducts [MeSnCl 3 (dbso) 2 ] and [Ph 3 SnCl(dbso)] were also prepared and included in the study. All complexes were studied by microanalysis and IR, NMR (1 H, 13 C and 119 Sn) and Mössbauer spectroscopies to investigate their structural properties. The six-coordinate species fac-[MeSnCl 3 (dbso) 2 ] and trans-[Ph 2 SnCl 2 (dbso) 2 ] were also studied by single crystal X-ray diffractometry. These compounds crystallize in the orthorhombic, Pbcn, and monoclinic space group P2 1 /c, respectively, as discrete neutral molecules with the tin(IV) atom in a distorted octahedral geometry and the two dbso ligands in cis and trans positions, respectively.
One-pot three-step thioconjugate addition-oxidation-Diels–Alder reactions of ethyl propiolate
Tetrahedron Letters, 2012
Ethyl propiolate undergoes one-pot three-step thioconjugate addition-oxidation-Diels-Alder cycloaddition when treated with a variety of thiols in the presence of catalytic base, meta-chloroperbenzoic acid, lithium perchlorate, and cyclopentadiene. The reaction of S-aryl thiols is catalyzed by trialkylamines, and the reaction of aliphatic thiols requires catalytic alkoxide base. Yields of the major diastereomer of the conveniently functionalized bicyclic products range from 47 to 81% depending upon the thiol reactant, which compares favorably to yields observed when the entire synthesis is performed step by step.