1486-75-5Relevant articles and documents
Oxidation of Alcohols by Metallic Nitrates Supported on Silica Gel
Nishiguchi, Takeshi,Asano, Fumi
, p. 1531 - 1535 (1989)
Several metallic nitrates supported on silica gel efficiently oxidized secondary alcohols and primary benzyl and allyl alcohols to the corresponding ketones and aldehydes under mild conditions.Especially, Cu(NO3)2 and Zn(NO3)2 are suitable for practical use.Silica gel was essential for the efficient oxidation in any case.Overoxidation of the formed aldehydes was not observed.Some mechanistic studies suggest that the key step of the process involves the formation of radical species.
METHOD FOR PRODUCING CYCLODODECANONE
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Page/Page column 27-28, (2008/06/13)
The invention relates to a method for producing cyclododecanone by reacting cyclododecen with dinitrogen, especially a method comprising steps (I) and (II): (I) producing cyclododecen by partially hydrating cyclododecatriene; (II) reacting the cyclododecen obtained in step (I) with dinitrogen monoxide, thereby obtaining cyclododecanone.
Flash vacuum thermolysis - Synthesis and characterization of unstabilized cycloalkenethiones
Briard, Emmanuelle,Levillain, Jocelyne,Ripoll, Jean-Louis,Dat, Yves,Marcual, Albert,Lange, Catherine
, p. 869 - 874 (2007/10/03)
The flash vacuum thermolysis (FVT) of cydoalkenyl allyl (or propargyl) sulfides 8, 9, 12, and 13 led, as the main thermal pathway, to the conjugated cycloalkenethiones 1, 3, and 5, resulting from a retro-ene reaction. These reactive thioketones, thus obtained in ca. 70% yield, have been characterized in the gas phase by mass spectrometry, and at low temperature by IR, UV/Vis and NMR spectroscopy. The polymerization of 1, 3, and 5 upon warming is generally more rapid than the other attempted reactions and only the [2 + 3] dipolar cycloaddition with diazomethane led in low yield, besides polymeric materials, to isomeric 1,3-dithiolanes 20 from cyclopentenethione 1. The obtention of the nonconjugated cycloalkenethiones 2 and 4, expected in the FVT of sulfides 10 and 11, has been confirmed only by UV/Vis spectroscopy at -196 °C, due to their rapid enethiolization. In the case of the large-ring sulfide 14, the (E) geometry of the double bond favoured the competitive retro-ene reaction yielding cyclododecene and propynethial; on the other hand, the FVT of the tricyclic gem-dithiol 15, a possible precursor of cyclobutenethione (7), led to vinyl thioketene (18), obtained by thermal ring opening of 7.
A Convenient and High Yielding Procedure for the Preparation of Isoselenocyanates. Synthesis and Reactivity of O-Alkylselenocarbamates.
Barton, Derek H. R.,Parekh, Shyamal I.,Tajbakhsh, Mahmoud,Theodorakis, Emmanouil A.,Tse, Chi-Lam
, p. 639 - 654 (2007/10/02)
A high yielding one pot procedure for the preparation of isoselenocyanate from the corresponding formamide is reported.Various aromatic and aliphatic primary amines were employed in order to prepare the isoselenocyanates to establish the generality of the procedure.O-Alkylselenocarbamates of various primary, secondary and tertiary alcohols were synthesized and their stability and comparative reactivity were studied.Radical deoxygenation of the selenocarbamate of a secondary and a tertiary alcohol was accomplished under various conditions.
New Desulfurizations by Nickel-Containing Complex Reducing Agents
Becker, Sandrine,Fort, Yves,Caubere, Paul
, p. 6194 - 6198 (2007/10/02)
Desulfurizations of saturated aliphatic or aromatic sulfoxides or sulfones are efficiently performed with nickel complex reducing agents (NiCRA's).The complete desulfurization of dithioketals can be effected in high yields with these reagents, while their half-desulfurization is efficiently achieved with 2,2'-bipyridine-modified nickel complex reducing agents (NiCRA-bpy).The desulfurization of vinyl thioethers, sulfoxides, and sulfones have been shown to be chemoselective, leaving the C-C double bond intact.The desulfurization of (E)-PhSO2(CH3)C=CHPh to cis-CH3CH=CHPh with NiCRA in the presence of quinoline is 95percent enantioselective.
β'β ANIONIC ELIMINATION OF CARBOXYLIC ESTERS
Aubert, Corinne,Begue, Jean-Pierre,Biellmann, Jean-Francois
, p. 5581 - 5590 (2007/10/02)
The elimination of lithium, magnesium and aluminium enolates of isobutyrates of medium ring cyclanols occurs in a syn fashion.A set of experimental procedures is presented.This elimination seems to be restricted to strained systems.The stereochemistry has been determined on stereospecifically deuterated cyclooctanol isobutyrates.The primary isotope effect kH/k2 was 3.0 +/- 0.1 and the secondary 1.1.The name β'β elimination is proposed for this syn elimination and related elimination.
TELLUROXIDE ELIMINATION BY DIRECT OXIDATION OF ALKYL PHENYL TELLURIDE
Uemura, Sakae,Ohe, Kouichi,Fukuzawa, Shin-ichi
, p. 895 - 898 (2007/10/02)
Treatment of sec-alkyl phenyl tellurides, except for the cyclohexyl system, with m-chloroperbenzoic acid(MCPBA) in diethyl ether readily afforded the corresponding olefins in good yields presumably via telluroxide elimination together with small amounts of alcohols and ketones.In the pri-alkyl and cyclohexyl cases the adducts between MCPBA and the tellurides were isolated as stable organotellurium(IV) compounds which gave similar elimination products by neat pyrolysis at 220-250 deg C.
Double Bond Geometry of the Alkenes produced by Oxidative Elimination of Alkyl Phenyl Selenides and Tellurides
Uemura, Sakae,Hirai, Yasuyuki,Ohe, Kouichi,Sugita, Nobuyuki
, p. 1037 - 1038 (2007/10/02)
Treatment of secondary-alkyl phenyl selenides with various oxidants affords the corresponding trans-alkene highly selectively irrespective of the amount of oxidant, while in the case of the tellurium analogues the double bond geometry of the product alkene depends markedly on the amount of oxidant, the trans-isomer being formed highly selectively with 1 equiv. oxidant and the proportion of the cis-isomer being increased with excess (2-10 equiv.) of oxidant.
Reaction of Organic Halides with Chlorotris(triphenylphosphine)cobalt(I)
Momose, Den-ichi,Iguchi, Kazuo,Sugiyama, Toshikazu,Yamada, Yasuji
, p. 1840 - 1853 (2007/10/02)
Reaction of various types of organic halides with a monovalent cobalt complex, chlorotris(triphenylphosphine)cobalt(I) is described.Reaction of benzylic monohalides, dihalides and trihalides with CoCl(Ph3P)3 gave a coupling product with formation of a carbon-carbon single bond, double bond and triple bond, respectively, under mild and non-basic conditions.Dehalogenation of non-benzylic vicinal dihalides with the reagent took place cleanly to give an olefin in high yield.Reductive coupling of allylic halides using the reagent afforded regioselectively a 1,5-diene with retention of the stereochemistry of the carbon-carbon double bond of the allylic halides used.By using this reaction, (E,E,E,E)-squalene was stereospecifically synthesized from (E,E)-farnesyl bromide.Reaction of halohydrins with CoCl(Ph3P)3 gave exclusively a ketone in the presence of an amine or olefin through an alkylcobalt intermediate.A 1,2-hydrogen shift is involved in this reaction.Keywords - chlorotris(triphenylphosphine)cobalt(I); coupling reaction; benzylic halides; allylic halides; synthesis of 1,5-diene; squalene; halohydrin; ketone synthesis.
Tests of a Piperidino Mask for the Protection of Functionalized Carbon Sites in Multistep Syntheses
Olofson, R. A.,Abbott, Duain E.
, p. 2795 - 2799 (2007/10/02)
Primary alkyl chlorides (R-Cl) are easily isolated in excellent yield after treatment of the appropriate N-alkylpiperidines (R-NC5H10) with α-chloroethyl chloroformate.The method is exemplified by the conversion of a variety of alkylpiperidines, including systems with other sensitive functionalities, to the respective chlorides in yields varying from 90 to 97percent.The potential significance of this process in drug congener preparation and in total synthesis is outlined.Similar fragmentations of N-sec-alkylpiperidines are described.
