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Gold-Catalyzed Formal Hexadehydro-Diels-Alder/Carboalkoxylation Reaction Cascades
A dual gold-catalyzed hexadehydro-Diels-Alder/carboalkoxylation cascade reaction is reported. In this transformation, the gold catalyst participated in the hexadehydro-Diels-Alder step, switching the mechanism from a radical type to a cationic one, and then the catalyst activated the resulting aryne to form an ortho-Au phenyl cation species, which underwent a carboalkoxylation rearrangement rather than the expected aryne-ene reaction.
Wang, Hong-Fa,Guo, Lin-Na,Fan, Zhi-Bo,Tang, Tian-Hua,Zi, Weiwei
supporting information
p. 2676 - 2681
(2021/04/12)

N-(4-Methoxyphenyl)-substituted bicyclic isothioureas: effect on morphology of cancer cells
Bicyclic isothioureas of N-(4-methoxyphenyl)-2-aminocycloalkane[d]thiazole type were obtained using intramolecular electrophilic cyclization of N-(cycloalk-2-enyl)-N′-(4-methoxyphenyl)thioureas. Isothiourea fused with sevenmembered ring caused noticeable
Alexeev, Alexander A.,Evdokimova, Anna V.,Kuznetsov, Sergei A.,Milaeva, Elena R.,Nurieva, Evgeniya V.,Zefirova, Olga N.
p. 288 - 290
(2021/06/07)

A lutidine-promoted photoredox catalytic atom-transfer radical cyclization reaction for the synthesis of 4-bromo-3,3-dialkyl-octahydro-indol-2-ones
Reported herein is a visible-light-catalyzed photoredox atom-transfer radical cyclization (ATRC) halo-alkylation of 1,6-dienes with α-halo-ketones as the ATRC reagent. This process exhibits high atom economy, high step economy, and high redox economy, which can directly construct a 4-bromo-3,3-dialkyl-octahydro-indol-2-one core under mild conditions in one pot, and lutidine is found to be the key promoter for this ATRC process.
Zhao, Quan-Sheng,Xu, Guo-Qiang,Xu, Ji-Tao,Wang, Zhu-Yin,Xu, Peng-Fei
supporting information
p. 2206 - 2209
(2020/02/26)

Silver-promoted cascade radical cyclization of γ,δ-unsaturated oxime esters with P(O)H compounds: synthesis of phosphorylated pyrrolines
A cascade radical cyclization was realized for the first silver-promoted imino-phosphorylation of γ,δ-unsaturated oxime esters, which provided a step-economical and redox-neutral route to access a variety of phosphorylated pyrrolines in good to excellent yields. Moreover, a new bulky trivalent phosphine ligand with a pyrroline motif was obtained through a deoxidation process.
Chen, Chen,Bao, Yinwei,Zhao, Jinghui,Zhu, Bolin
supporting information
p. 14697 - 14700
(2019/12/11)

Synthesis of pentacyclic compounds via intramolecular [3 + 2] photocycloaddition of cycloalkene linked naphthalenes
Intramolecular photocycloaddition reactions of cycloalkene linked naphthalenes lead to formation of pentacyclic compounds in a high yielding and stereoselective manner. Intramolecular [2 + 2] cycloadducts are formed initially in photoreactions of cycloalkene linked 1-cyanonaphthalenes. The initially formed intramolecular [2 + 2] cycloadducts absorb light at wavelengths used to promote the photochemical reactions and, as a result, they undergo efficient photocycloreversion to regenerate the starting substrates. In a less efficient competing process, the cycloalkene linked 1-cyanonaphthalenes react to form [3 + 2] intramolecular photoadducts, which do not absorb incident light under the conditions used. Consequently, these photoadducts become the major products in these processes. The relative configuration of the major diastereomers of the pentacyclic products formed from photoreactions of cyclopentene linked naphthalenes (cis-cis) differ from those (cis-trans) arising from the cyclooctene linked substrates. The results of theoretical calculations, which show that steric factors govern the preferred facial mode of intramolecular addition, are in good agreement with the stereochemical course of these photoreactions.
Maeda, Hajime,Uesugi, Tomoya,Fujimoto, Yasufumi,Mukae, Hirofumi,Mizuno, Kazuhiko
p. 198 - 206
(2017/02/10)

Hydroxylation versus Halogenation of Aliphatic C?H Bonds by a Dioxygen-Derived Iron–Oxygen Oxidant: Functional Mimicking of Iron Halogenases
An iron–oxygen intermediate species generated in situ in the reductive activation of dioxygen by an iron(II)–benzilate complex of a monoanionic facial N3ligand, promoted the halogenation of aliphatic C?H bonds in the presence of a protic acid and a halide anion. An electrophilic iron(IV)–oxo oxidant with a coordinated halide is proposed as the active oxidant. The halogenation reaction with dioxygen and the iron complex mimics the activity of non-heme iron halogenases.
Chatterjee, Sayanti,Paine, Tapan Kanti
supporting information
p. 7717 - 7722
(2016/07/07)

Synthesis of Secondary Unsaturated Lactams via an Aza-Heck Reaction
The preparation of unsaturated secondary lactams via the palladium-catalyzed cyclization of O-phenyl hydroxamates onto a pendent alkene is reported. This method provides rapid access to a broad range of lactams that are widely useful building blocks in alkaloid synthesis. Mechanistic studies support an aza-Heck-type pathway.
Shuler, Scott A.,Yin, Guoyin,Krause, Sarah B.,Vesper, Caroline M.,Watson, Donald A.
supporting information
p. 13830 - 13833
(2016/11/06)

Preparation of polycyclic compounds by intramolecular photospirocyclization and photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives
Photoreactions of 4-pentenyl-1-cyanonaphthalenes yield spirocyclic products along with [4?+?2] cycloadducts. Photoreactions of 5-phenyl derivatives produce a product having tricyclo[6.3.0.01,4]undecadiene skeleton. Formation of angular triquinanes takes place in photoreactions of cycloalkene-linked cyanonaphthalenes. The observation demonstrates that π–π arene ring interactions, steric hindrance, and suitable locations of reaction sites in syn and anti singlet exciplexes govern the modes followed in intramolecular photoreactions of 4-alkenyl-1-cyanonaphthalenes.
Maeda, Hajime,Wada, Hidenori,Mukae, Hirofumi,Mizuno, Kazuhiko
p. 29 - 41
(2016/11/16)

Trihaloisocyanuric Acid/Triphenylphosphine: An Efficient System for Regioselective Conversion of Epoxides into Vicinal Halohydrins and Vicinal Dihalides under Mild Conditions
A new synthetic method has been developed for the regioselective conversion of epoxides to vicinal chloro-/bromohydrins and vicinal dihalides by reaction with the system trihaloisocyanuric acid/tri?phenylphosphine in acetonitrile under mild and neutral conditions. The reactions proceed smoothly in high yield at room temperature and at reflux, respectively, over a short time.
De Andrade, Vitor S. C.,De Mattos, Marcio C. S.
p. 1381 - 1388
(2016/05/19)

The radical reaction from a fluorine-containing compound
PROBLEM TO BE SOLVED: To provide a radical reaction substitute solvent for carbon tetrachloride which has been used heretofore as a radical reaction solvent. SOLUTION: A chain fluorine-containing hydrocarbon represented by formula (1): CmH2m+2-nFn(wherein m is an integer of 3-10 and n is an integer of 1 to 2m+1) or a cyclic fluorine-containing hydrocarbon represented by formula (2): CpH2p-qFq(wherein p is an integer of 3-10 and q is an integer of 1 to 2p-1) is used as a solvent for various radical reactions. COPYRIGHT: (C)2011,JPO&INPIT
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Paragraph 0029-0030; 0031

(2017/01/05)

Bromination and accompanying rearrangement of the polycyclic oxetane 2,4-oxytwistane
Bromination of the polycyclic oxetane 2,4-oxytwistane (rac-(1R,3S,4R,7S,9R,11S)-2-oxatetracyclo-[5.3.1.03,11.04,9]undecane) was undertaken in order to form 2,4-dibromotwistane. The oxetane was subjected to the mild reagent combinatio
Rosenberg, Murray G.,Billing, Peter,Brecker, Lothar,Brinker, Udo H.
p. 8786 - 8799
(2015/02/19)

Stereoselective synthesis of cis,cis-configured vicinal triamines
The first stereoselective synthesis of a cis,cis-configured vicinal triamine was achieved, starting from N-cyclohexenylpyrrolidone (10). The reaction sequence consists of the stereoselective construction of the trans-configured 1,3-diamide 14, trans-to-ci
Schulte, Adrian,Saito, Susumu,Wünsch, Bernhard
supporting information
p. 5749 - 5756
(2014/10/15)

Bromine and iodine-cucurbit[6]uril complexes: Preparation and applications in synthetic organic chemistry
Iodine and bromine inclusion compounds were easily prepared by gas diffusion of the halogens using finely powdered CB[6]. A brown powder consisting of I2-CB[6]·4H2O and an orange one of (Br 2)4-CB[6]·10H2O were employed in several different reactions. I2-CB[6] can be used in catalytic reactions giving yields comparable to those reported in the literature. Br 2-CB[6] was effectively applied in electrophilic bromination of benzene and formation of bromohydrin. However, the radical substitution at cyclohexene could not be performed. Overall, based on these results, several applications can be envisioned for these complexes. This journal is the Partner Organisations 2014.
Reddy,Cavallini,Demets,Silva
supporting information
p. 2262 - 2264
(2014/06/09)

A [2 × 2] Cu4 molecular grid and a Mn5 cluster derived from a 1-(2-pyridyl)pyrazole based polytopic ligand - Synthesis, structure, magnetic properties and catalytic activity in the allylic oxidation of cyclohexene
The homoleptic [2 × 2] tetranuclear compound [Cu4(PyPzCAP) 4](NO3)4·8H2O (1) and the pentanuclear Mn(II) cluster [Mn5(PyPzCAP)6](ClO 4)4·4C6H6 (2) are self-assembled from the ditopic pro-ligand HPyPz-CAP [(5-methyl-1-(pyridin-2-yl) -N′-[1-(pyridin-2-yl)ethylidene]-1H-pyrazole-3-carbohydrazide)]. Complex 1 is almost a square grid, and all the Cu(II) centers show a distorted octahedral environment with an N4O2 chromophore. Complex 2 has a pentanuclear core with a trigonal bipyramidal arrangement of the Mn(II) atoms. The axial Mn centers bear an N3O3 chromophore and the equatorial centers have an N4O2 distorted octahedral arrangement. Complex 1 shows a ferromagnetic exchange interaction (J= +4.62 cm 1 and g= 2.05), whereas 2 shows weak an antiferromagnetic interaction (J= -2.73 cm 1 and g = 2.02). Both complexes 1 and 2 catalyze the allylic oxidation of cyclohexene to cyclohex-2-ene-1-one with good selectivity and an excellent overall turnover number.
Jana, Atanu,Konar, Saugata,Das, Kinsuk,Ray, Sangita,Golen, James A.,Rheingold, Arnold L.,El Fallah, Mohamed Salah,Mukherjee, Sanghamitra,Gupta, Samik,Pombeiro, Armando J.L.,Kar, Susanta Kumar
p. 51 - 60
(2013/10/22)

HEPATITIS B ANTIVIRAL AGENTS
The present invention includes a method of inhibiting, suppressing or preventing HBV infection in an individual in need thereof, comprising administering to the individual a therapeutically effective amount of at least one compound of the invention.
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Page/Page column 217

(2013/07/05)

Ammonium-directed olefinic epoxidation: Kinetic and mechanistic insights
The ammonium-directed olefinic epoxidations of a range of differentially N-substituted cyclic allylic and homoallylic amines (derived from cyclopentene, cyclohexene, and cycloheptene) have been investigated, and the reaction kinetics have been analyzed. The results of these studies suggest that both the ring size and the identity of the substituents on nitrogen are important in determining both the overall rate and the stereochemical outcome of the epoxidation reaction. In general, secondary amines or tertiary amines with nonsterically demanding substituents on nitrogen are superior to tertiary amines with sterically demanding substituents on nitrogen in their ability to promote the oxidation reaction. Furthermore, in all cases examined, the ability of the (in situ formed) ammonium substituent to direct the stereochemical course of the epoxidation reaction is either comparable or superior to that of the analogous hydroxyl substituent. Much slower rates of ring-opening of the intermediate epoxides are observed in cyclopentene-derived and cycloheptene-derived allylic amines as compared with their cyclohexene-derived allylic and homoallylic amine counterparts, allowing for isolation of these intermediates in both of the former cases.
Brennan, Meabh B.,Claridge, Timothy D.W.,Compton, Richard G.,Davies, Stephen G.,Fletcher, Ai M.,Henstridge, Martin C.,Hewings, David S.,Kurosawa, Wataru,Lee, James A.,Roberts, Paul M.,Schoonen, Anne K.,Thomson, James E.
p. 7241 - 7261
(2012/11/07)

A facile one-pot synthesis of α-halo,α-allylic aldehydes from α,α-dihalo ketones utilizing allylic zinc bromide
An efficient synthesis of various α-halo,α-allylic aldehydes from α,α-dihalo ketones using both cyclic (3-bromocyclohex-1-ene zinc bromide and (Z)-3-bromocyclobut-1-ene zinc bromide) and acyclic (allylzinc bromide and cinnamylzinc bromide) type of allylic organozinc bromide with DMF as base is described. A possible reaction mechanism is also proposed. Copyright
Wang, Xiaolei,Zhang, Songlin
experimental part
p. 96 - 102
(2012/03/10)

Efficient synthetic method for the preparation of allyl- and propargyl-epoxides by allylation and propargylation of α-haloketones with organozinc reagents
A simple, efficient, and non-metal catalyzed synthetic method for the preparation of substituted allyl- and propargyl-epoxides by allylation and propargylation of α-halo ketones with organozinc reagents in mild conditions is reported in this paper. The present method complements the existing synthetic methods due to some advantageous properties of the organozinc reagents such as availability, selectivity, operational simplicity and low toxicity.
Pan, Jie,Zhang, Min,Zhang, Songlin
experimental part
p. 1060 - 1067
(2012/04/10)

Bis- N -heterocyclic carbene palladium(IV) tetrachloride complexes: Synthesis, reactivity, and mechanisms of direct chlorinations and oxidations of organic substrates
This Article describes the preparation and isolation of novel octahedral CH2-bridged bis-(N-heterocyclic carbene)palladium(IV) tetrachlorides of the general formula LPdIVCl4 [L = (NHC)CH 2(NHC)] from LPdIICl2 and Cl2. In intermolecular, nonchelation-controlled transformations LPdIVCl 4 reacted with alkenes and alkynes to 1,2-dichlorination adducts. Aromatic, benzylic, and aliphatic C-H bonds were converted into C-Cl bonds. Detailed mechanistic investigations in the dichlorinations of alkenes were conducted on the 18VE PdIV complex. Positive solvent effects as well as kinetic measurements probing the impact of cyclohexene and chloride concentrations on the rate of alkene chlorination support a PdIV-Cl ionization in the first step. Product stereochemistry and product distributions from various alkenes also support Cl+-transfer from the pentacoordinated PdIV-intermediate LPdIVCl 3+ to olefins. 1-Hexene/3-hexene competition experiments rule out both the formation of π-complexes along the reaction coordinate as well as in situ generated Cl2 from a reductive elimination process. Instead, a ligand-mediated direct Cl+-transfer from LPd IVCl3+ to the π-system is likely to occur. Similarly, C-H bond chlorinations proceed via an electrophilic process with in situ formed LPdIVCl3+. The presence of a large excess of added Cl- slows cyclohexene chlorination while the presence of stoichiometric amounts of chloride accelerates both PdIV-Cl ionization and Cl+-transfer from LPdIVCl3 +. 1H NMR titrations, T1 relaxation time measurements, binding isotherms, and Job plot analysis point to the formation of a trifurcated Cl-...H-C bond in the NHC-ligand periphery as a supramolecular cause for the accelerated chemical events involving the metal center.
McCall, A. Scott,Wang, Hongwang,Desper, John M.,Kraft, Stefan
scheme or table
p. 1832 - 1848
(2011/04/15)

Copper-catalyzed asymmetric allylic alkylation of racemic cyclic substrates: Application of dynamic kinetic asymmetric transformation (DYKAT)
The copper-catalyzed asymmetric allylic alkylation (AAA) is of great interest in organic synthesis. This reaction was extensively studied using a broad range of substrates, ligands and organometallic reagents. However, the use of racemic substrates was still limited. Although some processes of kinetic resolution are reported in the literature, no examples of quantitative deracemization are described as is the case for the Pd-catalyzed allylic alkylation. We present here a full account of our investigations through the development of the first example of such a process in copper-catalyzed AAA. High enantioselectivities (up to 99% ee), scope of the reaction and mechanistic considerations are reported herein.
Langlois, Jean-Baptiste,Alexakis, Alexandre
supporting information; experimental part
p. 447 - 457
(2010/06/13)

Selective approach toward multifunctionalized lactams by lewis acid promoted PhSe group transfer radical cyclization
We have developed a regiospecific and highly stereoselective strategy for constructing the five-/six-membered monocyclic and bicyclic nitrogen heterocycle skeletons using PhSe group transfer radical cyclization of α-phenylseleno amido esters promoted by a Lewis acid (e.g., Yb(OTf)3) under UV irradiation. We obtained 5-/6-exo-trig mode cyclization products for the N-allyl/homoallyl substrates, whereas the enamide substrate gave 5-endo-trig ring closure.
Yu, Jin-Di,Ding, Wei,Lian, Gao-Yan,Song, Ke-Sheng,Zhang, Dan-Wei,Gao, Xiang,Yang, Dan
supporting information; experimental part
p. 3232 - 3239
(2010/08/19)

The halogenation of aliphatic C-H bonds with peracetic acid and halide salts
Hydrocarbons react with molar concentrations of peracetic acid and halide salts to yield predominantly monohalogenated products under optimum conditions, with chlorination being more oxidatively efficient than bromination. The alkane halogenation proceeds at ambient temperature and does not require a heavy-metal catalyst. The observed reactivity is consistent with a radical mechanism, in which the peracid initially reacts with the halide ions to yield halogen-atom radicals, which ultimately oxidize the hydrocarbon. Although the reactivity proceeds slightly more efficiently in acetonitrile, the halogenation protocol works well in water.
He, Yu,Goldsmith, Christian R.
supporting information; experimental part
p. 1377 - 1380
(2010/08/06)

Phase-vanishing reactions with ptfe (teflon) as a phase screen
Phase-vanishing reactions are triphasic reactions, which involve a reagent, a liquid perfluoroalkane, and a substrate. In a phase-vanishing reaction with PTFE tape as the phase screen instead of a liquid perfluoroalkane, there is no limitation related to the density of a phase and the denser phase can be in the top layer. The reactions were faster compared to traditional PV reactions, and it was possible to carry out sequential and tandem reactions and reactions under a reflux.
Van Zee, Nathan J.,Dragojlovic, Veljko
supporting information; experimental part
p. 3190 - 3193
(2009/11/30)

Ammonium-directed dihydroxylation of 3-aminocyclohex-1-enes: Development of a metal-free dihydroxylation protocol
Treatment of 3-aminocyclohex-1-enes with mCPBA in the presence of trichloroacetic acid gives the corresponding 1,2-anti-2,3-syn-1- trichloroacetoxy-2-hydroxy-3-aminocyclohexane with high levels of diastereoselectivity (90% de). This is consistent with a mechanism of oxidation involving hydrogen-bonded delivery of the oxidant by the allylic ammonium ion formed in situ, followed by highly regioselective ring-opening of the intermediate epoxide by trichloroacetic acid. The effect of conformational constraints upon the oxidation reaction is also examined. The Royal Society of Chemistry 2008.
Aciro, Caroline,Claridge, Timothy D. W.,Davies, Stephen G.,Roberts, Paul M.,Russell, Angela J.,Thomson, James E.
supporting information; experimental part
p. 3751 - 3761
(2009/02/04)

A highly stereoselective divergent synthesis of bicyclic models of photoreactive sesquiterpene lactones
Sesquiterpene lactones are natural stereochemically pure compounds, which show a number of biological activities. In order to study the reactivity of sesquiterpene lactones in biological systems, we describe herein the asymmetric synthesis of a simple mod
Fuchs, Sebastien,Berl, Valerie,Lepoittevin, Jean-Pierre
p. 1145 - 1152
(2008/02/06)

4-hydroxy-2-quinolones 125. Ethyl 3-bromo-2,4-dioxo-1,2,3,4- tetrahydroquinoline-3-carboxylates as potential brominating agents
The spatial structural features of 3-bromo-3-ethoxycarbonyl-2,4-dioxo-1,2, 3,4-tetrahydroquinolines have been studied by X-ray analysis. It has been experimentally confirmed that these compounds can be regarded as potential brominating agents.
Ukrainets,Sidorenko,Golovchenko
p. 1008 - 1013
(2008/09/19)

Kinetics and mechanism of monomolecular heterolysis of cage-like compounds: XVIII. Solvent effect on the rate of heterolysis of 3-bromocyclohexene. Correlation analysis of solvation effects
The kinetics of E1 dehydrobromination of 3-bromocyclohexene in 23 aprotic and 9 protic solvents were studied by the verdazyl technique. The reaction rate is described by the polarity, electrophilicity, and ionizing power parameters of the solvent. Nucleop
Ponomarev,Stambirskii,Dvorko,Bazil'chuk
p. 489 - 496
(2007/10/03)

Ionic liquid promoted regioselective monobromination of aromatic substrates with N-bromosuccinimide
Aromatic substrates were monobrominated regioselectively with NBS in the ionic liquid 1,3-di-n-butylimidazolium tetrafluoroborate [bbim]BF4 in 5 min at 28°C in excellent isolated yields (80-98%) in the absence of a catalyst.
Rajagopal,Jarikote,Lahoti,Daniel, Thomas,Srinivasan
p. 1815 - 1817
(2007/10/03)

Bromination of organic allylic compounds by using N,N′-dibromo-N,N′-1,2-ethane diyl bis(2,5-dimethyl benzene sulphonyl)amine
N,N′-Dibromo-N,N′-1,2-ethane diyl bis(2,5-dimethyl benzene sulphonyl)amine is an efficient brominating agent for bromination of allylic positions of different organic compounds. This reagent in presence of benzoyl peroxide can brominates the allylic positions of organic compounds in ambient conditions in carbon tetrachloride.
Khazaei, Ardeshir,Vaghei, Ramin Ghorbani,Karkhanei, Ebrahim
p. 2107 - 2113
(2007/10/03)

Trifluoromethylcyclohexane as a new solvent? Limits of use
Reactivity and stability of trifluoromethylcyclohexane (TFMC) has been investigated towards various reagents, in order to evaluate its possible use as solvent. TFMC is stable in most oxidizing conditions, indicating the protective effect of a fluoroalkyl substituent towards oxidation, and surprisingly, it is also very stable towards strong bases. TFMC has also been assessed as a chlorinated solvent substitute in some reactions. It is clearly adapted as a CCl4 substitute in allylic bromination reaction.
Legros, Julien,Crousse, Benoit,Bonnet-Delpon, Danièle,Bégué, Jean-Pierre,Maruta, Masamichi
p. 4067 - 4070
(2007/10/03)

Substituted 2-arylimino heterocycles and compositions containing them, for use as progesterone receptor binding agents
This invention relates to 2-arylimino heterocycles, including 2-arylimino-1,3-thiazolidines, 2-arylimino-2,3,4,5-tetrahydro-1,3-thiazines, 2-arylimino-1,3-thiazolidin-4-ones, 2-arylimino-1,3-thiazolidin-5-ones, and 2-arylimino-1,3-oxazolidines, and their use in modulating progesterone receptor mediated processes, and pharmaceutical compositions for use in such therapies.
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(2010/02/05)

X=Y-ZH Systems as potential 1,3-dipoles. Part 52: Fused-ring forming electrophile induced oxime→nitrone→cycloaddition cascades
Electrophile induced cyclisation of oximes onto endocyclic alkenes and exo-methylene cycloalkanes occurs stereo- and regio-specifically generating cis-fused bicyclic nitrones in good yield. Subsequent facially selective cycloaddition with N-methylmaleimid
Ali Dondas,Grigg, Ronald,Thibault, Sylvie
p. 7035 - 7045
(2007/10/03)

Indole derivatives as 5-HT1-like agonists
Compounds of formula (I) and pharmaceutically acceptable salts thereof, wherein R1 is a substituted alkylene; C3 -C7 cycloalkyl optionally substituted with HO; C3 -C6 alkenyl optionally substituted with aryl; C5 -C7 cycloalkenyl; or C3 -C6 alkynyl; R2 is H; halo; F3 C; NC; R8 R9 NOC; a substituted alkylene; R8 R9 NO2 S; R10 S(O)m ; R12 CON(R11); R10 SO2 N(R11); R8 R9 NOCN(R11); R10 O2 CN(R11); R13 (CH2)n CH=CH; or R7 O are selective 5-HT1 -like receptor agonists useful in the treatment of migraine, cluster headache, chronic paroxysmal hemicrania and headache associated with vascular disorders.
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(2008/06/13)

Zirconium-mediated intramolecular coupling of terminal alkynes and their subsequent carbonylation: Novel synthesis of seven- and eight-membered heterocycles
The development of a new method for the intramolecular coupling of terminal alkynes and for the synthesis of seven- and eight-membered benzoheterocyeles is reported. The key steps involve the generation of zirconocene-alkyne complexes from 2-bromoalkenes and the subsequent intramolecular carbometalation of olefins or acetylides. The 8-unsubstituted zirconabicyclopentenes were carbonylated to afford unexpected products and allow access to polyfunctionalized molecules from simple starting materials.
Barluenga, Jose,Sanz, Roberto,Fananas, Francisco J.
p. 1324 - 1336
(2007/10/03)

Intramolecular acryloxypalladation. Stereospecific synthesis of ring fused unsaturated α-methylene γ-butyrolactones.
The intramolecular carboxypalladation reaction [Pd(OAc)2 5 mol%, NaOAc 2 eq, O2, THF, rt] of 2-(2-Cycloalken-1-yle) propenoic acids yields ring fused α-methylene γ-butyrolactones with good yields. (75-80%).
Jabre-Truffert, Sylvaine,Waegell, Bernard
p. 835 - 836
(2007/10/03)

Radical Bromination of Cyclohexene in CCl4 by Bromine: Addition versus Substitution
The radical reaction of bromine (1E-2 - 1E-5 M) with cyclohexene in CCl4 in the light has been investigated.The reactions have been found to be highly reversible and controlled by both thermodynamics and the availability of Br2 and HBr as equilibrating ag
McMillen, D. W.,Grutzner, John B.
p. 4516 - 4528
(2007/10/02)

Palladium-catalyzed oxaspirocyclizations
Palladium-catalyzed oxidation of 1-(3-hydroxyalkyl) and 1-(4- hydroxyalkyl)-1,3-cycloalkadienes results in a stereocontrolled oxaspirocyclization. The reaction proceed via a spirocyclic (π- allyl)palladium intermediate, which is attacked by an acetate or a chloride nucleophile leading to an overall 1,4-addition across the diene. The intermediate (π-allyl) palladium complex was independently prepared and characterized. The stereochemistry of the 1,4-addition can be controlled to give either cis or trans 1,4-addition across the double bonds. The oxaspirocyclization was applied to the total synthesis of theaspirone.
Andersson,Nilsson,Backvall
p. 559 - 572
(2007/10/02)

Preparation of Benzothiophenes by Pd(0)-Catalyzed Intramolecular Cyclization of Allyl (and Propargyl) o-Iodophenyl Sulfides
Benzothiophenes are prepared by intramolecular Pd(0)-catalyzed Heck reaction of allyl o-iodophenyl sulfides.Pd(0)-Catalyzed intramolecular cyclization of o-iodophenyl propargyl sulfide in the presence of a hydride donor gives 3-methylene-2,3-dihydrobenzothiophene, which reacts with several enophiles in ene type reactions.However, allyl (and propargyl) aryl sulfides react with palladium(II) chloride to afford polymeric 2.
Arnau, Narcis,Moreno-Manas, Marcial,Pleixats, Roser
p. 11019 - 11028
(2007/10/02)

Deamination Reactions, 51. - Decomposition of Bicyclohexane-exo-6-diazonium Ions
The nitrous acid deamination of the amine 13, the copper(II)-induced cleavage of the nitrosourea 19, and the thermolysis of the nitrosoamide 20 were used to generate the diazonium ion 7.In contrast to previous work, performed in the presence of base, the neutral to weakly acidic conditions of the present study afforded substantial fractions (30-40percent) of bicyclohex-exo-6-yl products (15).Small quantities of bicyclohex-endo-6-yl (14), bicyclohex-2-yl (25, 26) and 3-cyclohexen-1-yl (27) derivatives were also detected, the latter arising by a 1,3-hydride shift.These results, unprecedented with higher homologs of 7, suggest a largely "classical" bicyclohex-6-yl cation (21) as the initially formed intermediate.Capture of 21 is thought to compete with disrotatory transformation to the cyclohexenyl cation 12. - Keywords: Bicyclohex-6-yl derivatives/ Diazonium ions/ Electrocyclic reactions/ Nucleophilic displacement
Kirmse, Wolfgang,Hellwig, Georg
p. 389 - 392
(2007/10/02)

HETEROGENEOUS ASYMMETRIC RING-OPENING REACTIONS OF PROCHIRAL EPOXIDES INCLUDED AS GUEST MOLECULES IN TRI-o-THYMOTIDE CLATHRATES.
Enantiomorphous tri-o-thymotide clathrates of prochiral oxiranes were submitted to the action of gaseous hydrogen halides.Ring-opening reactions ensued that differ from those reported in homogeneous phase, showing a considerable modification of the chemical reactivity of the external reagent in the host lattice.Chirality transfer from the host receptors to the guest products was also observed, but with a poor efficiency.
Gerdil, Raymond,Barchietto, Giacomo
p. 4685 - 4688
(2007/10/02)

6-BROMO-6-(TRIMETHYLSTANNYL)BICYCLOHEXANE AS A THERMAL PRECURSOR OF 1,2-CYCLOHEXADIENE
Flash vacuum pyrolysis and matrix-isolation studies of 6-bromo-6-(trimethylstannyl)bicyclohexane (1) gave evidence for the formation of 1,2-cyclohexadiene (2) from this precursor.At high temperatures (>600 deg C) 2 is not stable and fragmentates to 1-butene-3-yne (4) and ethylene.
Runge, Andreas,Sander, Wolfram
p. 5835 - 5838
(2007/10/02)

Homolytic Reactions of Phenyl Tribromomethyl Sulfone and Olefins
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Fields, D. L.,Shechter, H.
p. 3369 - 3371
(2007/10/02)

Reexamination of the Reaction of a "Graded Set" of Radicals with N-Bromosuccinimide: A Kinetic Argument Concerning the ? and ? States of Succinimidyl
The NBS brominations of methylene chloride with added substrates which yield stable radicals were reinvestigated.The proposal that these substrates would affect the ratio of β-bromopropionyl isocyanate (BPI)/bromodichloromethane, the solvent bromination product, was not substantiated.Bromination of 2,3-dimethylbutane, cyclohexene, and butadiene by NBS in CH2Cl2 plus vinylidene chloride gives essentially the same BPI/CHCl2Br ratios as in the presence of neopentane but large yields of brominated and polybrominated products.Similar reactions in the presence of up to 2.5 M benzene always yield BPI but also highly brominated benzene derivatives.BPI is detected in the NBS bromination of chloroform under all conditions and is the major product in the presence of vinylidene chloride.Photolysis of N-iodosuccinimide-I2 in CHCl3 gives β-iodopropionyl isocyanate as the chief product.None of these observations support the hypothesis of ? and ? states of the succinimidyl radical, while the NBS results appear consistent with competing S.-Br. chains.
Tanner, Dennis D.,Meintzer, Christian P.
p. 6584 - 6589
(2007/10/02)

BORON TRIFLUORIDE ETHERATE/HALIDE ION, A NOVEL REAGENT FOR THE CONVERSION OF ALLYL, BENZYL AND TERTIARY ALCOHOLS TO THE HALIDES
A combination of boron trifluoride etherate and halide ion is found to be an excellent reagent for the conversion of allyl, benzyl and tertiary alcohols to the halides.
Mandal, Arun K.,Mahajan, S. W.
p. 3863 - 3866
(2007/10/02)

The Reaction of Bromine with Cyclohexene in Carbon Tetrachloride. Part 1. Reactions in the Absence of Hydrogen Bromide; Presence of a Scavenger
The addition of bromine to cyclohexene in carbon tetrachloride solutions has been studied.Results are unreproducible, but when N-bromosuccinimide or N-bromophthalimide is also present to scavenge hydrogen bromide, a slower reaction, second-order in bromine, with reproducible rate constants is observed.This shows a negative overall activation energy.There may be terms in higher powers of , but the first-order term in bromine is too small to measure.A faster second phase of the reaction begins when all the N-bromo-imide initially present has reacted with the hydrogen bromide formed in side reactions, including those leading to 3-bromocyclohexene and (from adventitious water) to 2-bromocyclohexanol, and is of order 1.5 in bromine.
Byrnell, Charles J. A.,Coombes, Robert G.,Hart, Lionel S.,Whiting, Mark C.
p. 1079 - 1086
(2007/10/02)

Silylaminyl Radicals. Part 2. Free Radical Chain Halogenation of Hydrocarbons using N-Halogenobis(trialkylsilyl)amines
The liquid-phase halogenation of a number of hydrocarbons and of 1-chlorobutane by N-halogenobis(trialkylsilyl)amines has been studied using product analysis techniques.The reactions take place by free radical chain mechanisms which involve the propagation steps generalised in equations (A) and (B) (X=Br or Cl).At 353 K, the molar reactivities of toluene (benzylic C-H) and cyclohexane towards (R3Si)2N+RH(R3Si)2NH+R (A) R+(R3Si)2NXRX+(R3Si)2N (B) (Me3Si)2N are approximately equal and toluene is 5.2 times more reactive than perdeuteriotoluene.The relative rates of hydrogen abstraction by (Me3Si)2N and (ButMe2Si)2N from the primary, secondary, and tertiary C-H groups in 2-methylbutane show that the silylaminyl radicals are not only highly reactive but also sterically demanding.Thus, at 333 K the average primary C-H reactivity is 0.6 times that of the tertiary C-H towards attack by (Me3Si)2N, but 4.2 times that of the tertiary C-H towards attack by the more bulky (ButMe2Si)2N.Silylaminyl radicals are much more reactive in hydrogen abstraction than are analogous dialkylaminyl radicals and this difference is interpreted in terms of thermodynamic and polar effects which arise because of the ?-donor-?-acceptor nature of the trialkylsilyl substituent.
Cook, Malcolm D.,Roberts, Brian P.,Singh, Karamjit
p. 635 - 644
(2007/10/02)

The Reaction of Bromine with Cyclohexene in Carbon Tetrachloride. Part 2. Reactions in the Presence of Added Hydrogen Bromide, and of Imides, and in the Absence of Additives
The addition of bromine to cyclohexene in carbon tetrachloride containing added hydrogen bromide takes place rapidly, and is of first order in each of these species.When bromine is added to cyclohexene in solutions containing succinimide or phthalimide, the addition reaction follows an expression of order 1.5 in bromine and 0.5 in the imide.When no other component is present, the addition of bromine to cyclohexene is extremely sensitive to unintentional additives, but is usually of order 1.5 in bromine and of small positive order in water.We suggest reasonable reaction mechanisms for these processes, involving species stoicheiometrically equivalent to HBr3 and HBr5, and discuss their applicability to the second, fast phase of the scavenged reactions described in Part 1.
Hart, Lionel S.,Whiting, Mark C.
p. 1087 - 1092
(2007/10/02)

PHOTOADDITION REACTION OF 1,4-DIBROMO-2,5-PIPERAZINEDIONE WITH CYCLOHEXENE.
The photo-induced addition reaction of 1,4-dibromo-2,5-piperazinedione (1) with cyclohexene in acetonitrile gave 1:1-adducts left bracket 1-(2-bromocyclohexyl)-2,5-piperazinediones right bracket and 1:2-adducts left bracket 1,4-bis(2-bromocyclohexyl)-2,5-piperazinediones right bracket besides 3-bromocyclohexene, 1,2-dibromocyclohexane, and a solvent-incorporated product, trans-2-acetylamino-2-bromocyclohexane. Stereochemistry of the adducts was elucidated and mechanism of the addition reaction was discussed.
Itoh
p. 1705 - 1709
(2007/10/02)

Reactions of a Graded Set of Radicals with N-Bromosuccinimide; Two Transition States
The reactions of N-bromosuccinimide with a series of radicals have been studied.These reactions fall into two categories, the more reactive radicals producing ?-succinimidyl and the less reactive radicals producing ?-succinimidyl.The threshold for the changeover from one reaction domain to the other occurs with radicals less reactive than secondary alkyls.These results are interpreted with two transition states, an in-line transition state for the more reactive radicals and an out-of-plane transition state for the less reactive radicals. An upper limit of 18 kcal/mol is established for the enthalpy difference, HS? - HS?.Two new methods for generating S? radicals are indicated.
Tlumak, Robert L.,Skell Philip S.
p. 7267 - 7274
(2007/10/02)