- Benzosultam Synthesis by Gold(I)-Catalyzed Ammonium Formation/Nucleophilic Substitution
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The synthesis of benzosultams has been achieved through a gold(I)-catalyzed ammonium formation strategy. Starting from easily available N-(2-alkynyl)phenylsulfonyl azetidine derivatives, a cyclization reaction generated a spiroammonium gold intermediate t
- Pertschi, Romain,Weibel, Jean-Marc,Pale, Patrick,Blanc, Aurélien
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supporting information
p. 5616 - 5620
(2019/08/01)
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- Anionic Ring-Opening Polymerization of N-(tolylsulfonyl)azetidines to Produce Linear Poly(trimethylenimine) and Closed-System Block Copolymers
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The anionic ring-opening copolymerization of N-(p-tolylsulfonyl)azetidine (pTsAzet) and N-(o-tolylsulfonyl)azetidine (oTsAzet) produces poly(pTsAzet-co-oTsAzet) as a statistical copolymer. The pTsAzet/oTsAzet copolymerization is living and allows for the synthesis of poly(sulfonylazetidine) of target molecular weights with narrow dispersities. 1H NMR spectroscopy was used to monitor the kinetics of the polymerization and estimate the monomer reactivity ratios. It was found that the reactivity ratios for oTsAzet and pTsAzet at 180 °C are 1.66 and 0.60, respectively. The tosyl groups of p(pTsAzet-co-oTsAzet) were reductively removed to produce linear poly(trimethylenimine) (LPTMI). This represents the first route to LPTMI of controlled molecular weight and low dispersity. Finally, the slow kinetics of the sulfonylazetidine polymerization facilitated the synthesis of a block copolymer without requiring the sequential addition of monomer. Specifically, pTsAzet, oTsAzet, and (N-p-toluenesulfonyl-2-methylaziridine) (pTsMAz) were combined in solution. pTsMAz selectively polymerizes to form the first block at moderate temperature. After consumption of pTsMAz, the temperature was increased to copolymerize pTsAzet and oTsAzet and produce the block copolymer p(pTsMAz)-b-p(pTsAzet-co-oTsAzet).
- Reisman, Louis,Rowe, Elizabeth A.,Jackson, Enrique M.,Thomas, Christian,Simone, Tomekia,Rupar, Paul A.
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supporting information
p. 15626 - 15630
(2018/12/11)
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- HBr–DMPU: The First Aprotic Organic Solution of Hydrogen Bromide
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HBr and DMPU (1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone) form a room-temperature-stable complex that provides a mild, effective, and selective hydrobrominating reagent toward alkynes, alkenes, and allenes. HBr–DMPU could also replace other halogenating reagents in the halo-Prins reaction, ether cleavage, and deoxy-bromination reactions.
- Li, Zhou,Ebule, Rene,Kostyo, Jessica,Hammond, Gerald B.,Xu, Bo
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supporting information
p. 12739 - 12743
(2017/09/25)
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- Magnesium bis(monoperoxyphthalate) hexahydrate as mild and efficient oxidant for the synthesis of selenones
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A new, efficient and mild method for the direct oxidation of selenides to selenones using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) has been developed. Noteworthy this transformation proceeds at room temperature, employs a cheap and safety oxi
- Temperini, Andrea,Curini, Massimo,Rosati, Ornelio,Minuti, Lucio
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supporting information
p. 1267 - 1271
(2014/06/24)
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- Gold-catalyzed substitution reaction with ortho-alkynylbenzoic acid alkyl ester as an efficient alkylating agent
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ortho-Alkynylbenzoic acid alkyl esters behave as alkylating agents in combination with gold catalysts. The reaction with alcohols occurs smoothly in the presence of catalytic amounts of Ph3PAuCl and AgOTf under mild conditions to produce the corresponding ether products in high yields. The protocol is also useful for Friedel-Crafts alkylation and N-alkylation of sulfonamides. The reaction likely proceeds through the gold-induced in situ construction of leaving groups and subsequent nucleophilic attack of nucleophiles, such as alcohols, aromatic compounds, and sulfonamides.
- Aikawa, Haruo,Tago, Sakie,Umetsu, Kazuteru,Haginiwa, Naomichi,Asao, Naoki
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experimental part
p. 1774 - 1784
(2009/06/20)
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- Synthesis and characterization of N-arylsulfonylazetidines
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(Chemical Equation Presented) A convenient method for the synthesis of N-arylsulfonyl azetidines using N-(3-bromopropyl)-arylsulfonamide with cesium carbonate and potassium iodide in DMF is reported. The reaction conditions are optimized and seven N-aryls
- Tan, Songde,Chen, Yiwen,Zingaro, Ralph A.,Reibenspies, Joseph H.
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p. 1229 - 1232
(2008/12/20)
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- Rh(I)-catalyzed CO gas-free carbonylative cyclization of organic halides with tethered nucleophiles using aldehydes as a substitute for carbon monoxide
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The CO gas-free carbonylative cyclization of organic halides, with tethered nitrogen, oxygen, and carbon nucleophiles, with aldehydes as a substitute for carbon monoxide can be achieved in the presence of a catalytic amount of a rhodium complex. The reaction involves the decarbonylation of the aldehyde by the rhodium catalyst, and the successive carbonylation of an organic halide utilizing the rhodium carbonyl that is formed in situ. Aldehydes having electron-withdrawing groups showed a higher ability to donate the carbonyl moiety.
- Morimoto, Tsumoru,Fujioka, Masahiko,Fuji, Koji,Tsutsumi, Ken,Kakiuchi, Kiyomi
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p. 625 - 634
(2008/02/06)
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- A new method for the preparation of nitrogen-containingheterocycles using diphenylsulfonium triflates
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Various nitrogen heterocycles were produced by the reactions of ω-bromoalkyldiphenylsulfonium or diphenylsyylsulfonium triflates with nitrogen nucleophiles. Further, the reactions of diphenylstyrylsulfonium triflates with N-metalated phthalimide and imida
- Yamanaka, Hiroyuki,Yamane, Yoshinobu,Mukaiyama, Teruaki
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p. 2813 - 2826
(2007/10/03)
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- Efficient synthesis of azetidine through N-trityl- or N- dimethoxytritylazetidines starting from 3-amino-1-propanol or 3- halopropylamine hydrohalides
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Efficient synthetic routes for the preparation of azetidine starting from commercially available 3-amino-1-propanol or 3-halopropylamine hydrohalides are reported. First, the appropriate N-trityl- or N-dimethoxytrityl protected tosyloxy- or halopropylamines were prepared. These precursors were then cyclized into the N-trityl- or N-dimethoxytritylazetidines. The N-protecting groups were removed in the presence of perchloric acid giving the hydrogen perchlorate salt of azetidine. The latter compound was transformed into its free base using a strong base under anhydrous conditions. The relatively expensive 4,4'-dimethoxytrityl chloride and less expensive trityl chloride used in these synthetic procedures were recycled in good yields. Azetidine hydrogenperchlorate can be used to prepare N-substituted azetidines without the need to isolate the free azetidine.
- Huszthy,Bradshaw,Krakowiak,Wang,Dalley
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p. 1197 - 1207
(2007/10/02)
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- Selective synthesis of heterocyclic compounds through the intramolecular substitution of phenylselenonyl group by nitrogen or carbonyl oxygen in amides
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Nitrogen heterocycles were produced by the oxidation of N-[ω-(phenylseleno)alkyl]-p-toluenesulfonamides through the intramolecular substitution of the resultant phenylselenonyl group by the nitrogen atom. By the oxidation of the corresponding benzamides,
- Toshimitsu,Hirosawa,Tanimoto,Uemura
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p. 4017 - 4020
(2007/10/02)
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- The influence of altered amidic resonance on the infrared and13C and15N NMR spectrosocopic characterstics and barriers to rotation about the N-C(O) bond in some anilides and toluamides
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In order to provide physicochemical evidence for or against amidic resonance, three of anilides and toluamides have been investigated by infrared spectroscopy and 13C and 15N NMR, and barriers to rotation for several toluamides have
- Bennet,Somayaji,Brown,Santarsiero
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p. 7563 - 7571
(2007/10/02)
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- Organic Synthesis Using PTC: Part 8 - Synthesis of Macrocylic Systems Containing Nitrogen and/or Oxygen as Heteroatom(s)
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Reactions of p-toluene/benzenesulphonamides with p-toluenesulphonate ester of diols under liquid-liquid and solid-liquid phase transfer (PT) conditions give cyclic N-p-toluenesulphonyl or N-benzenesulphonyl derivatives with 1:1 and/or 2:2 stoichiometries.Thus, the cyclic system containing N and/or O as heteroatom(s) have been procured usimg this procedure.
- Singh, Paramjit,Jain, Anupa
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p. 790 - 792
(2007/10/02)
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- RING-CLOSURE REACTIONS. XXIV. KINETICS OF FORMATION OF MEDIUM - AND LARGE-RING N-TOSYLAZACYCLOALKANES. ROLE OF RING STRAIN ON MEDIUM-RING FORMATION
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The kinetics of closure of N-tosylazacycloalkanes from the anions derived from N-tosyl-ω-bromoalkylamines have been investigated in 99percent aqueous Me2SO.Rate constants and effective molarities (EM) have now been obtained for the ring sizes 8-13, 17, an
- Galli, Carlo,Gargano, Patrizia,Mandolini, Luigi
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p. 653 - 658
(2007/10/02)
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- RING-CLOSURE REACTIONS. XXV. WHY ARE STRAINED SMALL RINGS SO EASILY FORMED IN INTRAMOLECULAR NUCLEOPHILIC SUBSTITUTION REACTIONS?
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The leaving group effect (kBr/kCl) has been determined for two typical series of SN2 cyclisation reactions in the ring size range of 3 to 6 in order to probe the effect of ring strain on transition state structure.The general increase of the magnitude of the leaving group effect on going from the less strained to the more strained ring systems indicates that bond making and bond breaking is significant also in the small ring transition states.The apparent unimportance of strain in the products to the ease of closure of the smallest rings is tentatively explained by the hypothesis that the adverse effect of ring strain is partially offset by a significant reduction of non-bonded interactions in the transition states.
- Casadei, Maria Antonietta,Martino, Alessandro di,Galli, Carlo,Mandolini, Luigi
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p. 659 - 664
(2007/10/02)
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- Ring-closure Reactions. Part 23. Kinetics of Formation of Three- to Seven-membered-ring N-Tosylazacycloalkanes. The Role of Ring Strain in Small- and Common-sized-ring Formation
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Rates of cyclisation of a series of anions derived from N-tosyl-ω-bromoalkylamines to nitrogen heterocycles with three to seven members in Me2SO-H2O (99:1) have been studied.Rates vary markedly with ring size in the order 5 > 3 > 6 > 7 ca. 4.First order rate constants for cyclisation have been translated into effective molarities (EM) with reference to an appropriate intermolecular model reaction.Comparison of the present results with available literature data on SN2 ring-closure reactions leading to small- and common-sized rings reveals that the ease of formation of three-membered rings is much more structure-dependent than that of the higher homologues.This remarkable behaviour is believed to parallel the unique way in which the stability of three-membered rings is affected by structure.As a rule, the ease of cyclisation appears to bear an inverted relationship to the assumed strain energy of the ring product.The apparent opposition of this rule to earlier conclusions in the literature is discussed.
- Martino, Alessandro Di,Galli, Carlo,Gargano, Patrizia,Mandolini, Luigi
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p. 1345 - 1350
(2007/10/02)
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- Nuclear Magnetic Resonance as a Means of Assessing Structure versus Reactivity Relationships in Alicyclic Compounds
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Proton-carbon-13 coupling constants (J13C,H) have been measured for three series of N-substituted azacycloalkanes.Structural features of the alicyclic compounds, as revealed by this and other n.m.r.techniques, reflect the strain present in the ring and can be used as a guide to predict ring-closure reactivity.Deviations from such structure versus reactivity relationships are found with highly strained small rings.Hence, it must be stressed that meaningful trends in the behaviour of ring compounds can only be revealed when large homologous series are examined.Literature X-ray structural studies are also exploited in order to comment on the situation in small rings and on their peculiar ring-closure tendency.It is suggested that, although some of the experimental features and behaviour can be accounted for in terms of strain, others, in the case of three-membered rings, are to be attributed to the presence of ?-aromaticity.Because of this, these three-membered ring compounds can efficiently gain stabilization by resonance interaction with exocyclic conjugative substituents: n.m.r. evidence is given on this point.
- Cerichelli, Giorgio,Galli, Carlo,Lillocci, Claudio,Luchetti, Luciana
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p. 725 - 728
(2007/10/02)
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