- Synthesis of 2-substituted ±-(2R,3R,5R)-tetrahydrofuran-3,5-dicarboxylic acid derivatives
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An efficient synthesis of 2-substituted (±)-(2R,3R,5R)-tetrahydrofuran-3,5-dicarboxylic acid derivatives has been developed. Starting from 5-norborne-2-ol, the key intermediate (±)-methyl 5,6-exo(isopropylidenedioxy)-2-oxabicyclo[2.2.1]heptane-3-exo-carboxylate (15) was synthesized in an efficient six-step sequence. The key transformation is the base-catalyzed methanolysis-rearrangement of (±)-6,7-exo,exo-(isopropylidenedioxy)-4-exo-iodo-2-oxabicyclo [3.2.1]octan-3-one (14). Further manipulation of the 3-substituent of (±)-methyl 5,6-exo,exo-(isopropylidenedioxy)-2-oxabicyclo[2.2.1] heptane-3-exo-carboxylate (15) followed by deprotection of the diol moiety and ring opening catalyzed by RuCl3/NaIO4 gave the title compounds in good yield.
- Wang,Wang,Chen,Gentles,Sowin
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- Total Synthesis of Δ12-Prostaglandin J3: Evolution of Synthetic Strategies to a Streamlined Process
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The total synthesis of Δ12-prostaglandin J3(Δ12-PGJ3, 1), a reported leukemia stem cell ablator, through a number of strategies and tactics is described. The signature cross-conjugated dienone structural motif of 1 was forged by an aldol reaction/dehydration sequence from key building blocks enone 13 and aldehyde 14, whose lone stereocenters were generated by an asymmetric Tsuji–Trost reaction and an asymmetric Mukaiyama aldol reaction, respectively. During this program, a substituent-governed regioselectivity pattern for the Rh-catalyzed C?H functionalization of cyclopentenes and related olefins was discovered. The evolution of the synthesis of 1 from the original strategy to the final streamlined process proceeded through improvements in the construction of both fragments 13 and 14, exploration of the chemistry of the hitherto underutilized chiral lactone synthon 57, and a diastereoselective alkylation of a cyclopentenone intermediate. The described chemistry sets the stage for large-scale production of Δ12-PGJ3and designed analogues for further biological and pharmacological studies.
- Nicolaou,Pulukuri, Kiran Kumar,Yu, Ruocheng,Rigol, Stephan,Heretsch, Philipp,Grove, Charles I.,Hale, Christopher R. H.,ElMarrouni, Abdelatif
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p. 8559 - 8570
(2016/07/11)
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- PHARMACEUTICAL COMPOSITIONS AND METHODS FOR RELIEVING PAIN AND TREATING CENTRAL NERVOUS SYSTEM DISORDERS
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Patients susceptible to or suffering from disorders, such as central nervous system disorders, which are characterized by an alteration in normal neurotransmitter release, such as dopamine release (e.g., Parkinsonism, Parkinson's Disease, Tourette's Syndrome, attention deficient disorder, or schizophrenia), are treated by administering a compound of Formulas (1 or 2), as described herein. The compounds of Formulas (1 and 2) are also useful for treating pain, and treating drug addiction, nicotine addiction, and/or obesity. The compounds can exist as individual stereoisomers, racemic mixtures, diastereomers and the like.
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Page/Page column 79-80
(2008/06/13)
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- Five-membered carbocyclic and heterocyclic inhibitors of neuraminidases
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Disclosed are compounds of the formula: which are useful for inhibiting neuraminidases from disease-causing microorganisms, especially, influenza neuraminidase. Also disclosed are compositions and methods for preventing and treating diseases caused by microorganisms having a neuraminidase, processes for preparing the compounds and synthetic intermediates used in these processes.
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- Ring-opening metathesis - Cross-metathesis reactions (ROM-CM) of substituted norbornadienes and norbornenes
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Ring-opening metathesis - cross-metathesis reactions (ROM-CM) of substituted norbornadienes and norbornenes were investigated. The reactions with symmetrical 2,3-disubstituted norbornadienes were found to be highly chemoselective, with the ROM reactions occurring only on the less substituted or less sterically hindered double bonds regardless of the electronic nature of the substituents, giving highly substituted cyclopentenes in moderate to good yields. This study provides an efficient method for the stereoselective synthesis of highly substituted cyclopentenoids. Long-range electronic effect of a remote substituent on unsymmetrical norbornenes in the ROM-CM reactions was also investigated. Low levels of regioselectivities were observed (50:50 to 69:31) with various remote substituents on the norbornenes.
- Mayo, Peter,Tam, William
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p. 9513 - 9525
(2007/10/03)
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- Remote substituent effects on the oxymercuration of 2-substituted norbornenes: An experimental and theoretical study
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The effect of a remote substituent on regioselectivity in the oxymercuration of 2-substituted norbornenes has been investigated experimentally and theoretically using density functional theory (DFT). Regioselectivities of 1:1 to 14:1 were observed with various 2-substituted norbornenes. Exo-2-substituted norbornenes always gave greater regioselectivities compared to the corresponding endo-2-substituted norbornenes. The effects of solvents on the regioselectivity have also been examined, and ethereal solvents were found to be the best choice giving the optimal yield and regioselectivity. The relative rate of oxymercuration was estimated by competition experiments. The least reactive substrate (X = OAc) gave the highest regioselectivity. According to DFT predictions, the increased difference between the reaction barriers that results in the greater regioselectivity is correlated directly with the larger polarity of the C=C double bond, which is attacked by the mercury and oxygen. A number of stable exo and endo conformers were predicted. All exo conformers show the same polarity of the double bond, while some endo conformers have a reversal of this polarity. All the conformers except those with the OAc substituent are very close in energy and thus should react. The existence of a mixture of endo conformers with the C=C double bond of opposite polarity clearly explains a decrease in regioselectivity for the endo species. The origin of the greatest regioselectivity for the OAc-2-norbornenes lies in the fact that the conformer with the largest polarity is notably lower in energy than others due to an internal C-H-O hydrogen bond.
- Mayo,Orlova,Goddard,Tam
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p. 5182 - 5191
(2007/10/03)
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- Synthesis of norborn-5-en-2-one and its homologue
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Diels-Alder reaction of cyclopentadiene and 1,3-cyclohexadiene with propiolic ester 6 under thermal and high pressure conditions gave an epimer mixture of ketoester 8 and 10, subsequently converted into bicyclic ketones 1 and 2.
- Minuti,Taticchi,Marrocchi,Costantini,Wenkert
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p. 707 - 710
(2007/10/03)
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- New synthesis of 2-aminobicyclo[2.1.1]hexane-2,5-dicarboxylic acid-I (ABHxD-I), a potent metabotropic receptor agonist
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A new versatile synthesis of racemic ABHxD-I, a potent mGluR agonist, is presented. The synthesis was achieved by means of a Wolff rearrangement, which converted a 3-diazobicyclo[2.2.1]heptan-2-one into a bicyclo[2.1.1]hexane derivative. (C) 2000 Elsevier Science Ltd.
- Conti, Paola,Kozikowski, Alan P.
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p. 4053 - 4056
(2007/10/03)
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- Oxygen transfer reactions from an oxaziridinium tetrafluoroborate salt to olefins
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Oxaziridinium 5 efficiently epoxidises olefins. It reacts as an electrophilic reagent and does not transfer its oxygen to deactivated double-bonds or carbonyl functions. Epoxidation of cyclic allylic acetates shows a remarkable diastereoselectivity leading to the syn isomer. We propose that the epoxidation reaction proceeds through a one-step process.
- Lusinchi, Xavier,Hanquet, Gilles
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p. 13727 - 13738
(2007/10/03)
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- A versatile cobalt(II)-Schiff base catalyzed oxidation of organic substrates with dioxygen: Scope and mechanism
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Cobalt(II) complex 1a-f derived from Schiff bases act as efficient catalysts during the oxidation of wide range of organic substrates(e.g. alkenes, alcohols, benzylic compounds and aliphatic hydrocarbons) with dioxygen in the presence of aliphatic aldehydes or ketones or ketoesters. EPR studies on 1a-f complexes suggest that the aliphatic carbonyl compounds promote the formation of a cobalt(II)-superoxo species responsible for the oxidation of organic compounds. These studies also demonstrate the role of ligands on cobalt in controlling the chemoselectivity of these oxidations. A plausible mechanistic rational is also provided for these oxidations.
- Punniyamurthy,Bhatia, Beena,Reddy, M. Madhava,Maikap, Golak C.,Iqbal, Javed
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p. 7649 - 7670
(2007/10/03)
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- Enantiomers of cis- and trans-3-(4-propyl-cyclopent-2-enyl) propyl acetate. A study on the bioactive conformation and chiral recognition of a moth sex pheromone component
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The enantiomers of cis- and trans-3-(4-propyl-cyclopent-2-enyl) propyl acetate, which are conformationally constrained analogues of (Z)-5-decenyl acetate (1), a sex pheromone component of the turnip moth, Agrotis segetum, have been synthesized and tested using the elcctrophysiological single-sensillum technique. The analogues mimic a cisoid and transoid conformation of 1, respectively. In addition, the enantiomers of each of the cis- and trans-isomers are conformationally constrained analogues of enantiomeric cisoid and transoid conformations of 1. Thus, the compounds prepared and tested are well suited to investigate the nature of the bioactive conformation of the natural pheromone component 1 and the chiral sense of its interaction with the receptor. Electrophysiological single-sensillum recordings show that the activity of the most active cis-isomer, which has a (1S,4R)-configuration, is more than two orders of magnitude higher than that of the most active trans-isomer. Furthermore, the (1S,4R)-isomer is at least 100 times more active than its enantiomer. These results strongly support a previously proposed cisoid bioactive conformation of 1. Furthermore, the (1S,4R)-configuration of most active stereoisomer identifies the chiral sense of the interaction between the natural pheromone component 1 and its receptor.
- Gustavsson, Anna-Lena,Larsson, Mattias C.,Hansson, Bill S.,Liljefors, Tommy
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p. 2173 - 2183
(2007/10/03)
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- α-Acetyl- and α-Cyanovinyl 2,4-Dinitrophenyl Carboxylate as Useful Ketene Equivalents for the Diels-Alder Reaction
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Two ketene equivalents (5 and 35) have been developed for use in the Diels-Alder reaction. These dienophiles exhibit a marked increase in reactivity in comparison with the more conventional acetoxyacrylonitrile. Conversions of the cycloadducts to the requisite ketones occurs under mild, and moderate to high yielding conditions.
- MaGee, David I.,Lee, May Ling
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p. 786 - 788
(2007/10/03)
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- BECKMANN FRAGMENTATION VERSUS BECKMANN REARRANGEMENT IN DEHYDRONORCAMPHOR DERIVATIVES
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Attempted Beckmann rearrangement of dehydronorcamphor oxime resulted in Beckmann fragmentation and dimerization of the intermediate cyanomethylcyclopenta-1,3-diene isomers.The dienes can be trapped by N-phenylmaleimide to yield two isomeric crystalline adducts.When the olefin in dehydronorcamphor oxime is effectively blocked, Beckmann rearrangement takes place to provide stereochemically pure bicyclic lactam.
- VerHaeghe, Daniel G.,Weber, Gregory S.,Pappalardo, Paul A.
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p. 4041 - 4044
(2007/10/02)
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- Acid-Catalyzed Hydrolysis of Bridged Bi- and Tricyclic Compounds. XXVI. The Mechanisms of Formation of the Hydration Products of 2-Norbornen-5-one
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The acid-catalyzed hydration of 2-norbornen-5-one (1) in 5 mol dm-3 HClO4 at 358 K produces, according to GLC analyses, exo-5-hydroxy-2-norbornanone (2), 2-oxabicycloctan-3-one (3), which is in equilibrium with cis-3-hydroxycyclopentaneacetic acid (5), and 2-oxabicyclooctan-3-one (4).The former lactone (3) is unstable and rearranges slowly to the latter (4).The ketoalcohol (2) is formed via the slow protonation of norbornenone at C(3) and via subsequent hydration of the carbocation.The lactones are formed via complicated routes started by the protonation of norbornenone at C(2), and comprising 3- and 2-cyclopentaneacetic acid (7 and 9) as unstable intermediate products.
- Lajunen, Martti,Lahti, Marjo,Heimo, Satu
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p. 771 - 776
(2007/10/02)
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- New Ketene Equivalents for the Diels-Alder Reaction. Vinyl Sulphoxide Cycloadditions
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1-Phenlsulphinyl-1-trimethylsilylethene and phenyl vinyl sulphoxide have been shown to be effective ketene equivalents for the Diels-Alder reaction.
- Williams, Richard Vaughan,Lin, Xu
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p. 1872 - 1873
(2007/10/02)
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- Norticyclic-Norbornenyl Cation. Isotopic Perturbation and Isotopic Scrambling
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The stable carbocation which is formed from either 3-nortricyclyl or norbornenyl precursors was studied with the deuterium isotopic perturbation method. 13C NMR signals from the two carbons, expected to be videly split by isotopic perturbation if an equilibrium exist between rapidly interconverting norbornenyl structures, showed only a small, temperature-independentsplitting.It was concluded that a maximum of ca. 1percent of the equilibrating norbornenyl ions might be present.A single structure (nortricyclyl with extensive charge delocalization) adequately represents the cation.This is verified by di-13C-labeled cation precursor, which also provides the complete set of J12 13C-13C coupling constants.NMR spectra of the deuteriated ion and of 1,7-di-13C-labeled ion revealed that the cation is undergoing at least three different scrambling processes below 0 deg C.The spectra show that the fastest process involves reversible skeletal rearrangement to the bicycloheptenyl cation.A still slower process including a hydride shift also occurs.The observed rearrangements ultimately result in complete scrambling of all carbons and hydrogens in the cation.
- Saunders, Martin,Jarret, Ronald M.,Pramanik, Pradip
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p. 3735 - 3739
(2007/10/02)
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- Synthesis, Thermolysis, and Photolysis of the Azoalkanes Spiro3,7>non-4-ene-8,2'-dioxolane> and 4,5-Diazatricyclo3,7>non-4-en-8-one: On the Mechanism of the Oxadi-?-methane Rearrangement of 5-Norbornen-2-one
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4,5-Diazatricyclo3,7>non-4-en-8-one (4) and spiro3,7>non-4-ene-8,2'-dioxolane (5) were prepared starting from bicyclohept-5-en-2-one (1) by cycloaddition with 4-phenyl-4H-1,2,4-triazole-3,5-dione (PTAD) to the corresponding urazole 7, followed by the acetalization to the urazole 9 and subsequent hydrolysis and oxidation.The regioselectivity of the PTAD-cycloaddition leading to urazole 7 was confirmed by an X-ray analysis.Direct and benzophenone-sensitized photolyses of azoalkane 5 gave the tricycloalkane 13, while in the thermolysis also the pyrazole 12 was formed.Direct and benzophenone-sensitized photolyses of azoalkane 4 yielded bicyclohept-5-en-2-one (1), tricyclo2,7>heptan-3-one (2), and bicyclohept-3-en-6-one (3).Thermolysis gave only the bicyclic ketones 1 and 3.It is postulated that the photolysis and thermolysis of azoalkane 4 first lead to diazenyl diradicals 19a, b, which are differentiated in their chemical behavior on account of spin state multiplicities (singlet versus triplet) and electronic configurations (D?,? versus D?,?).Formation of the oxadi-?-methane-type 1,3-diradical 20 by denitrogenation involving double C-N cleavage represents a minor product channel.
- Adam, Waldemar,De Lucchi, Ottorino,Hill, Karlheinz,Peters, Eva-Maria,Peters, Karl,Schnering, Hans Georg von
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p. 3070 - 3088
(2007/10/02)
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- Synthesis of Precursors of C4 and C5 Cumulenones
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Bicyclohept-5-en-2-one was condensed with 2,2-dimethyl-1,3-dioxan-4,6-dione in the presence of titanium tetrachloride/pyridine to yield 5-(bicyclohept-5'-en-2'-ylidene)-2,2-dimethyl-1,3-dioxan-4,6-dione (6a) which on pyrolysis at 520-560 deg/0.01 mm gave acetone, carbon dioxide, cyclopentadiene and butatrienone.In the same way 5-(7'-oxabicyclohept-5'-en-2'-ylidene)-2,2-dimethyl-1,3-dioxan-4,6-dione (6b) was prepared from 7-oxabicyclohept-5-en-2-one and on pyrolysis at 570 deg/0.01 mm it gave acetone, carbon dioxide, furan and butatrienone.Alkylation of 2-trimethylsiloxybicyclohepta-2,5-diene with phenylthiomethyl chloride with titanium tetrachloride as catalyst followed by condensation with 2,2-dimethyl-1,3-dioxan-4,6-dione gave an endo/exo mixture of 5-(3'-phenylthiomethylbicyclohept-5'-en-2'-ylidene)-2,2-dimethyl-1,3-dioxan-4,6-dione.The structure of the endo isomer was established by X-ray crystallography.Oxidation of the phenylthiomethyl compound with m-chloroperbenzoic acid yielded the sulfoxide which was converted by boiling in carbon tetrachloride into 5-(3'-methylenebicyclohept-5'-en-2'-ylidene)-2,2-dimethyl-1,3-dioxan-4,6-dione (8).Preliminary studies on the fragmentation of compound (8) have shown that at 450 deg/0.01 mm it is converted into acetone, carbon dioxide and products showing ketene absorption at 2140 cm-1.The formation of pentatetraenone has not been established with certainty.The 3'-phenylsulfonylmethyl, phenylselenyl and methyl derivatives of (6a) are also described.
- Brown, Roger F. C.,Coulston, Karen J.,Eastwood, Frank W.,Gatehouse, Bryan M.,Guddatt, Luke W.,et al.
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p. 2509 - 2524
(2007/10/02)
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- A serendipitous, high yield conversion of norbornenone to tricyclo2,7>octan-4-one
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Simmons-Smith cyclopropanation of the trimethylsilyl enol ether of norbornenone has been found to generate the 2-trimethylsilyl ether of homoquadricyclene, homoketonization of which affords the symmetrical tricyclo2,7>octan-4-one regiospecifically with high stereoselectivity favoring inversion of configuration.
- Ragauskas, Arthur J.,Stothers, J.B.
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p. 2254 - 2256
(2007/10/02)
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- Fragmentation of Homoallylic Alkoxides. Preparation of 1-(3'-Cyclopentenyl)-2-alkanones from 2-Substituted Bicyclohept-5-en-2-ols
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The potassium 2-substituted bicyclohept-5-en-2-alkoxides derived from alcohols 2-9 at 30 deg C in hexamethylphosphoric triamide (HMPA) afford 1-(3'-cyclopentenyl)-2-alkanones 10-19 via heterolytic C(1),C(2)-allylic bond cleavage in the substrate alkoxide followed by intramolecular protonation of the resultant transient allylic anion.
- Snowden, Roger L.
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p. 1031 - 1038
(2007/10/02)
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- Oxidative Decyanation of Secondary Nitriles to Ketones
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Procedures for the oxidative decyanation of secondary nitriles to ketones involve (1) iodination of N-(trialkylsilyl)ketenimines derived from secondary nitriles and subsequent hydrolysis of the α-iodo nitriles with silver oxide, (2) addition of nitrosobenzene to N-(trialkylsilyl)ketenimines, (3) conversion of secondary nitriles to α-(phenylthio) nitriles and subsequent hydrolysis with N-bromosuccinimide in aqueous acetonitrile, and (4) preparation of α-hydroperoxy nitriles by direct oxygenation of anions of secondary nitriles and subsequent reductive hydrolysis with stannous chloride followed by sodium hydroxide.The latter general procedure was applied to various secondary nitriles bearing dialkyl, aryl and alkyl, and diaryl substituents to provide ketones in good yield and was extended to the oxidative decyanation of α,β-unsaturated nitriles to furnish α,β-unsaturated ketones.
- Freerksen, Robert W.,Selikson, Sandra J.,Wroble, Randall R.,Kyler, S. Keith,Watt, David S.
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p. 4087 - 4096
(2007/10/02)
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- Nucleophilic Exchange Reactions at 1-Chloroquadricyclane: 1,5- and 1,7-Dehydroquadricyclane as Reactive Intermediates.
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Quadricyclane was metalated at position 1 to 1b in high yield by the complex of butyllithium and tetramethylethylenediamine or by a mixture of butyllithium and potassium tert-butoxide.Numerous 1-substituted quadricyclanes were accessible via 1b.Nuclophilic substitution products were obtained by the reaction of 1-chloroquadricyclane with organolithium compounds, lithium amides, and with lithium ethylthiolate (in the presence of a bulky strong base), which could be isomerized to the corresponding norbornadienes.Mechanistic investigations have shown that 1,7- and 1,5-dehydroquadricyclane (4 and 5) were involved as reactive intermediates.The nucleophilic substitution of optical active 1-chloroquadricyclane with lithium dimethylamide proceeded with 96percent racemization.This result is in accord with an elimination-addition mechanism passing over 4 and 5.
- Baumgaertel, Otto,Szeimies, Guenter
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p. 2180 - 2204
(2007/10/02)
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- SILAFUNCTIONAL COMPOUNDS IN ORGANIC SYNTHESIS. XVIII. OXIDATIVE CLEAVAGE OF THE SILICON-CARBON BOND IN ALKENYLFLUOROSILANES TO CARBONYL COMPOUNDS: SYNTHETIC AND MECHANISTIC ASPECTS
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Alkenyltrifluorosilanes are readily oxidized by one equivalent of MCPBA in DMF even at -50 deg C to give the corresponding carbonyl compounds via cleavage of the carbon-silicon bond.With three equivalent of MCPBA a concomitant cleavage of the carbon-carbon bond occurs.A plausible mechanism of these new types of oxidation has been discussed.Oxidation with DABCO*2H2O2 has also been described.
- Tamao, Kohei,Akita, Munetaka,Kumada, Makoto
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- Efficient Stereocontrolled Total Syntheses of Racemic and Natural Brefeldin-A
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Brefeldin-A, an antiobiotic fungal metabolite, has been obtained in both racemic and natural forms through a direct approach that employs norbornenone and 6-heptyn-2-ol as the basic starting materials.
- Drian, Claude Le,Greene, Andrew E.
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p. 5473 - 5483
(2007/10/02)
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- DETERMINATION DE PURETE ENANTIOMERIQUE PAR RMN13C DANS LES SERIES DES BICYCLO(2.2.1.)-HEPTANE ET BICYCLO(2.2.1.)-HEPTENE
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N.M.R.13C peak assignments were established for each diastereoisomeric ketal form of norbornanone (+/-), or norbornenone (+/-).This method offers an attractive route for the determination of the optical purity of these ketones.
- Bordeaux, D.,Gagnaire, G.
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p. 3353 - 3356
(2007/10/02)
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- Two Methoxycarbonylketen Equivalents as Dienophiles in the Diels-Alder Reaction
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Methyl methoxypropiolate and methyl (phenylthio)propiolate give Diels-Alder adducts with 1,3-dienes; the adducts with cyclopentadienes give methyl 3-oxobicyclohept-5-ene-2-carboxylates on hydrolysis.
- Gupta, Indranil,Yates, Peter
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p. 1227 - 1228
(2007/10/02)
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- PREPARATION OF METHYL 10-OXO-15S-HYDROXYPROSTA-5E,13Z-DIENOATE
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The synthesis of methyl 10-oxo-15S-hydroxyprosta-5E,13Z-dienoate
- Arndt, Henry C.,Rajani, Cynthia
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p. 2365 - 2368
(2007/10/02)
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- REGIOSELECTIVE ADDITIONS OF ELECTROPHILES TO OLEFINS REMOTELY PERTURBED. THE CARBONYL GROUP AS A HOMOCONJUGATED ELECTRON DONATING SUBSTITUENT.
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Electrophiles attack preferentially at the C(5) position of 2-norborn-5-enone and 2-bicyclooct-5-enone whereas the C(6) position is preferred for 2-chloronorborn-5-ene-2-carbonitriles and 2-chlorobicyclooct-5-ene-2-carbonitriles.
- Carrupt, Pierre-Alain,Vogel, Pierre
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p. 2563 - 2566
(2007/10/02)
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- A New Total Synthesis of Epifenchone and Dehydrocamphenilone
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A new and simple method with good yields for the total synthesis of the title substances 5 and 9 is described.Methylation of 3, 4, and 8 with CH3I/LCIA in THF under reflux yields the geminal dimethylnorbornanones 5, 6, and 9.
- Dworan, Erich,Buchbauer, Gerhard
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p. 2357 - 2359
(2007/10/02)
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- Deamination Reactions. 35. Decomposition of 5-Norbornene-2-diazonium Ions. Derivatives of Bicyclohept-2-ene
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Photolysis of 5-norbornen-2-one tosylhydrazone (4) in aqueous sodium hydroxide afforded 4percent of 3-norpinen-2-ol (3) in addition to 5-norbornen-2-ol (5, 10percent) and nortricyclanol (6, 86percent). 3 arises from 5-norbornene-2endo-diazonium ions (2) as shown by the nitrous acid deamination of the epimeric amines 1 and 7. 3-Norpinen-2-one (12) was isolated by oxidation of the deamination products followed by preparative g.l.c. 3 and 12 were synthesized independently from norpinan-2-one (9) via sulfenylation and sulfoxide pyrolysis.The norbornene -> norpinene rearrangement is slightly enhanced by 1-OCH3.The deamination of 1-methoxy-5-norbornen-2endo-amine (14) produced 10percent of 12, as compared to 5.6percent of 3 from 1.
- Kirmse, Wolfgang,Knoepfel, Norbert,Loosen, Karin,Siegfried, Rainer,Wroblowsky, Heinz-Juergen
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p. 1187 - 1191
(2007/10/02)
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- COMPETING CHELETROPIC REACTIONS OF DIFLUOROCARBENE WITH VARIOUS 2-SUBSTITUTED NORBORNADIENES
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Norbornadienes substituted at C2 with electron donating, conjugating, and withdrawing groups react with difluorocarbene to give a ratio of 1,2-to homo-1,4 adducts, which reflects a diminishing response of electrophilic character in the carbene.
- Jefford, Charles W.,Phan Thanh Huy
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p. 755 - 758
(2007/10/02)
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- Die Synthese von 6exo-substituierten p-Toluolsulfonsaeure-estern
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The preparation of hitherto unknown p-toluenesulfonates of 6exo-substituted 2endo-norbornanols is described.
- Fischer, Walter,Grob, Cyril A.,Sprecher, Georg von,Waldner, Adrian
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p. 816 - 823
(2007/10/02)
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