- Visible Light-Promoted Magnesium, Iron, and Nickel Catalysis Enabling C(sp3)-H Lactonization of 2-Alkylbenzoic Acids
-
A mild and practical C(sp3)-H lactonization protocol has been achieved by merging photocatalysis and magnesium (iron, nickel) catalysis. A diverse range of 2-alkylbenzoic acids with a variety of substitution patterns could be transformed into the corresponding phthalide products. Based on the mechanistic experimentation and reported prior studies, a possible mechanism for the benzylic oxidative lactonization reaction was proposed with the hypothetic photoactive ternary complex formed between the 2-alkylbenzoic acid substrate, magnesium ion, and bromate anion.
- Li, Sasa,Su, Mincong,Sun, Jie,Hu, Kunjun,Jin, Jian
-
supporting information
p. 5842 - 5847
(2021/07/31)
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- Metal-Free Addition of Benzyl Halides to Aldehydes Using Super Electron Donors: Access to 3,4-Dihydroisocoumarins and 1,2-Diarylethanols
-
We report here the intermolecular metal-free addition reaction of functionalized benzyl halides to aldehydes using a super electron donor (SED). The metal-free and mild conditions allowed the formation of 3,4-dihydroisocoumarins and 1,2-diarylethanols with unprecedented functional group tolerance.
- Spitz, Cédric,Matteudi, Mélanie,Tintori, Guillaume,Broggi, Julie,Terme, Thierry,Vanelle, Patrice
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p. 15736 - 15742
(2020/12/23)
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- Calcium(II)- And Triflimide-Catalyzed Intramolecular Hydroacyloxylation of Unactivated Alkenes in Hexafluoroisopropanol
-
We report an efficient intramolecular hydroacyloxylation of unactivated alkenes, offering a streamlined access to relevant γ-lactones, which features the utilization of either a calcium(II) salt or triflimide as a catalyst in hexafluoroisopropanol. This method could be applied to the synthesis of natural products and the late-stage functionalization of natural and bioactive molecules. Additionally, DFT computations were used to elucidate the twist of reactivity observed between the hydroamidation and hydroacyloxylation of unactivated alkenes regarding the formation of 5- and 6-membered rings.
- Qi, Chenxiao,Yang, Shengwen,Gandon, Vincent,Leb?uf, David
-
supporting information
p. 7405 - 7409
(2019/10/02)
-
- Cooperative iodine and photoredox catalysis for direct oxidative lactonization of carboxylic acids
-
A new method for the formation of γ- and δ-lactones from carboxylic acids through direct conversion of benzylic C-H to C-O bonds is described. The reaction is conveniently induced by visible light and relies on a mild cooperative catalysis by the combination of molecular iodine and an organic dye.
- Duhamel, Thomas,Mu?iz, Kilian
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p. 933 - 936
(2019/01/23)
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- Palladium/Acid Relay Catalyzed Tandem Heck Coupling/6-Endo Cyclization between ortho-Halogenated Benzoates and Unactivated Terminal Alkenes for the Synthesis of 1-Isochromanones
-
We report a unique and expeditious route to synthesize 1-isochromanone derivatives through palladium catalyzed tandem Heck coupling/6-endo hydroacyloxylation cyclization between readily available ortho-halogenated benzoates and unactivated alkenes. Various 2-bromo or 2-iodo benzoates can be coupled efficiently with a broad range of alkenes to afford functionalized 1-isochromanones in high yields. Significantly, this cost-efficient and easy-to-handle synthetic methodology will have great prospect application in the synthetic and medicinal chemistry. (Figure presented.).
- Wen, Zhen-Kang,Ge, Xiao-Min,Zhao, Ze-Kai,Chao, Jian-Bin
-
supporting information
p. 983 - 988
(2019/01/30)
-
- First TDAE Reactivity Using Benzonitrile Derivatives as Substrates and Its Application to the Synthesis of 3-Substituted Isochroman-1-ones
-
The first TDAE-initiated reaction between benzonitrile derivatives as substrates and substituted benzaldehydes to form substituted hydroxyethylbenzonitrile derivatives is reported. The 2-hydroxyethyl benzonitrile derivatives thus formed were good candidat
- Khoumeri, Omar,Terme, Thierry,Vanelle, Patrice
-
p. 2617 - 2623
(2018/05/03)
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- Visible-Light-Induced C-O Bond Formation for the Construction of Five- and Six-Membered Cyclic Ethers and Lactones
-
Visible-light-induced intramolecular C-O bond formation was developed using 2,4,6-triphenylpyrylium tetrafluoroborate (TPT), which allows the regiocontrolled construction of cyclic ethers and lactones. The reaction is likely to proceed through the single-electron oxidation of the phenyl group, followed by the formation of a benzylic radical, thus preventing a competing 1,5-hydrogen abstraction pathway. Detailed mechanistic studies suggest that molecular oxygen is used to trap the radical intermediate to form benzyl alcohol, which undergoes cyclization. This new approach serves as a powerful platform by providing efficient access to valuable five- and six-membered cyclic ethers and lactones with a unified protocol.
- Im, Honggu,Kang, Dahye,Choi, Soyeon,Shin, Sanghoon,Hong, Sungwoo
-
supporting information
p. 7437 - 7441
(2018/11/27)
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- Scalable Electrochemical Dehydrogenative Lactonization of C(sp2/sp3)-H Bonds
-
A practical, electrochemical method is developed for the direct dehydrogenative lactonization of C(sp2/sp3)-H bonds under external oxidant- and metal-free conditions, delivering diverse lactones, including coumarin derivatives with excellent regioselectivity. The scalable nature of this newly developed electrochemical process was demonstrated on a 40 g scale following an operationally simple protocol. The remote lactonization of C(sp3)-H bonds would constitute an important synthetic advance toward electrochemical C-O bond formation.
- Zhang, Sheng,Li, Lijun,Wang, Huiqiao,Li, Qian,Liu, Wenmin,Xu, Kun,Zeng, Chengchu
-
supporting information
p. 252 - 255
(2018/01/17)
-
- Cobalt-Catalyzed Coupling of Benzoic Acid C?H Bonds with Alkynes, Styrenes, and 1,3-Dienes
-
A method for cobalt-catalyzed, carboxylate-directed functionalization of arene C?H bonds is reported. Alkynes, styrenes, and 1,3-dienes can be coupled with benzoic acids to provide cyclic products in good yields. The reactions proceed in the presence of a
- Nguyen, Tung Thanh,Grigorjeva, Liene,Daugulis, Olafs
-
supporting information
p. 1688 - 1691
(2018/01/15)
-
- Photoinduced Regioselective Lactonization of ortho-Iodobenzoic Acids with Alkenes: Synthesis of 3,4-Dihydroisocoumarin Derivatives
-
A photoinduced strategy for the synthesis of a variety of 3,4-dihydroisocoumarins has been realized. The reactions proceeded from ortho -iodobenzoic acids and alkenes through a photodehalogenative lactonization with NaHCO 3 as the only additive in dimethyl sulfoxide (DMSO) to provide the desired products in moderate to good yields. This method offers a simple, mild, and environmentally friendly route to 3,4-dihydroisocoumarin derivatives.
- Zhang, Xiao,Huang, Binbin,Yang, Chao,Xia, Wujiong
-
p. 131 - 135
(2017/10/06)
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- Photocatalyzed synthesis of isochromanones and isobenzofuranones under batch and flow conditions
-
Photocatalyzed reactions of 2-(alkoxycarbonyl)benzenediazonium tetrafluoroborates with various alkenes afforded isochromanones in good yields, according to a mechanism that was investigated. The advantage of using highly soluble esters rather than carboxylic acids as starting compounds became evident when the reactions were performed under flow conditions. On the other hand, when 2-vinylbenzoic acid derivatives were employed as reagents, isobenzofuranones were obtained together with unprecedented benzo[e][1,3]oxazepin-1(5H)-ones, with the latter derived from incorporation of the solvent (acetonitrile).
- Anselmo, Manuel,Moni, Lisa,Ismail, Hossny,Comoretto, Davide,Riva, Renata,Basso, Andrea
-
p. 1456 - 1462
(2017/08/02)
-
- Mechanistic analysis of a copper-catalyzed C-H oxidative cyclization of carboxylic acids
-
We recently reported that carboxylic acids can be oxidized to lactone products by potassium persulfate and catalytic copper acetate. Here, we unravel the mechanism for this C-H functionalization reaction using desorption electrospray ionization, online electrospray ionization, and tandem mass spectrometry. Our findings suggest that electron transfer from a transient benzylic radical intermediate reduces Cu(ii) to Cu(i), which is then re-oxidized to Cu(ii) in the catalytic cycle. The resulting benzylic carbocation is trapped by the pendant carboxylate group to give the lactone product. Formation of the putative benzylic carbocation is supported by Hammett analysis. The proposed mechanism for this copper-catalyzed oxidative cyclization process differs from earlier reports of analogous reactions, which posit a substrate carboxylate radical as the reactive oxidant.
- Banerjee, Shibdas,Sathyamoorthi, Shyam,Du Bois,Zare, Richard N.
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p. 7003 - 7008
(2017/10/05)
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- A Photocatalytic Meerwein Approach to the Synthesis of Isochromanones and Isochromenones
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A visible-light RuII photoredox Meerwein synthesis of isochromanones and isochromenones is described starting from diazonium salts of differently substituted anthranilic acids and various alkenes. This approach has allowed the reliable and effi
- Crespi, Stefano,J?ger, Stefanie,K?nig, Burkhard,Fagnoni, Maurizio
-
p. 2147 - 2153
(2017/04/24)
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- Copper-Catalyzed Oxidative Cyclization of Carboxylic Acids
-
A method for converting C-H to C-O bonds through oxidative cyclization of carboxylic acids to generate lactone products is described. The reaction employs catalytic amounts of Cu(OAc)2 and potassium persulfate as the terminal oxidant and is performed open to air in an aqueous acetic acid solvent system. Preliminary mechanistic studies suggest that substrate oxidation likely proceeds by sulfate radical anion and that the Cu catalyst has no influence on the product-determining step. These conclusions differ from related investigations that propose the intermediacy of a carboxylate radical.
- Sathyamoorthi, Shyam,Du Bois
-
supporting information
p. 6308 - 6311
(2016/12/23)
-
- Manganese-Catalyzed ortho-C?H Alkenylation of Aromatic N?H Imidates with Alkynes: Versatile Access to Mono-Alkenylated Aromatic Nitriles
-
So far, the direct C?H alkenylation of aromatic nitriles with alkynes has not been achieved. Herein, we discribe the first manganese-catalyzed C?H alkenylation of aromatic N?H imidates to access mono-alkenylated aromatic nitriles. The reaction is accelerated by the presence of a catalytic amount of sodium pivalate. This protocol is also highlighted by the simple catalytic system, good compatibility of functional groups, and excellent mono-/dialkenylation selectivity as well as E/Z stereoselectivity. (Figure presented.).
- Yang, Xiaoxu,Jin, Xiqing,Wang, Congyang
-
supporting information
p. 2436 - 2442
(2016/08/16)
-
- Synthesis and application of benzyl-TMS derivatives as bench stable benzyl anion equivalents
-
The regioselective benzylic metalation of toluenes using BuLi/KO tBu/TMP(H) (LiNK metalation conditions) and subsequent transmetalation to Si by reaction with TMSCl provides a general one-pot procedure for the synthesis of substituted benzyltrimethylsilanes. ArCH 2Si(Me)3 derivatives are bench stable reagents yet can serve as benzyl anion equivalents under mild reaction conditions. Following activation with fluoride they can successfully participate in a wide range of additions to both non-enolizable and enolizable carbonyls. In addition, their use in the synthesis of isochromanones and trifluoromethylated amines is illustrated. The broad synthetic scope and mild practical conditions of use for ArCH2Si(Me)3 reagents demonstrate their general potential as benzyl anion equivalents.
- Das, Manas,O'Shea, Donal F.
-
p. 6448 - 6460
(2013/07/26)
-
- Expeditious synthesis of 3,4-dihydroisocoumarins and phthalides using the Heck-Matsuda reaction
-
Several 3,4-dihydroisocoumarins and phthalides were synthesized by an effective Heck-Matsuda reaction involving an ortho carboxybenzenediazonium salt with a series of styrenes bearing electron donating and electron withdrawing groups, methylvinyl ketone,
- Da Penha, Eduardo T.,Forni, José Augusto,Biajoli, André F.P.,Correia, Carlos Roque D.
-
scheme or table
p. 6342 - 6345
(2011/12/21)
-
- Chiral lithium amide mediated asymmetric synthesis of 3-aryl-3,4- dihydroisocoumarins
-
An asymmetric synthesis of 3-aryl-3,4-dihydroisocoumarins using the reaction of laterally lithiated 4,4-dimethyl-2-(o-tolyl)oxazoline with aromatic aldehydes, in the presence of an external chiral ligand, gave products with enantiomeric excess (ee) in the range of 60-70%. ARKAT USA, Inc.
- Sharma, Arvind Kumar,Maheshwary, Yogita,Singh, Paramjit,Singh, Kamal Nain
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scheme or table
p. 54 - 62
(2010/10/19)
-
- A new approach to the synthesis of 3,4-dihydroisocoumarin derivatives
-
A new, simple, one-step synthesis of 3-substituted 3,4-dihydroisocoumarins is developed. The products are obtained by the reaction of o-methoxycarbonyl arenediazonium bromides with unsaturated compounds in the presence of CuBr as a catalyst.
- Obushak, Mykola D.,Matiychuk, Vasyl S.,Turytsya, Victor V.
-
experimental part
p. 6112 - 6115
(2010/01/18)
-
- Original preparation of conjugates for antibody production against Amicoumacin-related anti-microbial agents
-
Amicoumacins are natural products with potent anti-ulcerogenic and anti-bacterial activities, and have been isolated from different Bacillus genera. They belong to a family of 3,4-dihydroisocoumarin derivatives bearing hydroxylated amino acid side chains.
- Shinkaruk, Svitlana,Bennetau, Bernard,Babin, Pierre,Schmitter, Jean-Marie,Lamothe, Valerie,Bennetau-Pelissero, Catherine,Urdaci, Maria C.
-
supporting information; experimental part
p. 9383 - 9391
(2009/04/11)
-
- Titanocene(III) chloride mediated radical-induced synthesis of 3,4-dihydroisocoumarins: synthesis of (±)-hydrangenol, (±)-phyllodulcin, (±)-macrophyllol and (±)-thunberginol G
-
A radical-promoted synthesis of 3,4-dihydroisocoumarins has been achieved in moderate to good yields using titanocene(III) chloride (Cp2TiCl) as the radical initiator. The total synthesis of four naturally occurring dihydrocoumarins hydrangenol, phyllodulcin, macrophyllol and thunberginol G has been accomplished using the radical technology. Cp2TiCl was prepared in situ from commercially available titanocene dichloride (Cp2TiCl2) and Zn-dust in THF under argon.
- Mandal, Samir Kumar,Roy, Subhas Chandra
-
experimental part
p. 11050 - 11057
(2009/04/11)
-
- Direct lactone formation by using hypervalent iodine(III) reagents with KBr via selective C-H abstraction protocol
-
We have developed a new and reliable method for the direct construction of biologically important aryl lactones and phthalides from carboxylic and benzoic acids, using a combination of hypervalent iodine(III) reagents with KBr.
- Dohi, Toshifumi,Takenaga, Naoko,Goto, Akihiro,Maruyama, Akinobu,Kita, Yasuyuki
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p. 3129 - 3132
(2008/02/09)
-
- Radical-mediated synthesis of 3,4-dihydroisocoumarins: total synthesis of hydrangenol
-
A radically promoted synthesis of 3,4-dihydroisocoumarins has been achieved in moderate to good yields using titanocene(III) chloride (Cp2TiCl) as the radical initiator. The total synthesis of (±)-hydrangenol has been completed using this radical technology. Cp2TiCl was prepared in situ from commercially available titanocene dichloride (Cp2TiCl2) and Zn-dust in THF under argon.
- Mandal, Samir Kumar,Roy, Subhas Chandra
-
p. 4131 - 4134
(2008/02/03)
-
- A case of pictet-spengler revisited: Application to the synthesis of dihydroisocoumarins
-
The reaction of Pictet-Spengler was revisited, and its modified conditions were applied to develop a general methodology toward the synthesis of dihydroisocoumarins containing a no-electron rich aromatic ring.
- Choukchou-Braham,Mostefa-Kara,Cheikh,Didi,Villemin
-
p. 169 - 178
(2007/10/03)
-
- Iridium-catalyzed oxidative lactonization and intramolecular Tishchenko reaction of δ-ketoaldehydes for the synthesis of isocoumarins and 3,4-dihydroisocoumarins
-
Two new cyclizations of ketoaldehydes have been developed using an Ir-ligand bifunctional catalyst. Oxidative lactonization of δ- ketoaldehydes proceeded smoothly at room temperature to give coumarin derivatives in excellent yields. Intramolecular Tishche
- Suzuki, Takeyuki,Yamada, Taichiro,Watanabe, Kazuhiro,Katoh, Tadashi
-
p. 2583 - 2585
(2007/10/03)
-
- Oxidation of 3-arylisochromans by dimethyldioxirane. An easy route to substituted 3-arylisocoumarins
-
The selective oxidation of the two different benzylethereal position of 3-arylisochromans by dimethyldioxirane as a function of different substituents on the aromatic rings was studied. The easy oxidation of these compounds was exploited for a new easy ac
- Bovicelli, Paolo,Lupattelli, Paolo,Crescenzi, Benedetta,Sanetti, Anna,Bernini, Roberta
-
p. 14719 - 14728
(2007/10/03)
-
- Electron-transfer-induced reductive cleavage of phthalans: Reactivity and synthetic applications
-
The behavior of phthalan (1a) was investigated under conditions of electron transfer from alkali metals in aprotic solvents. Reaction with lithium in the presence of a catalytic amount of naphthalene in THF led to the reductive cleavage of an arylmethyl carbon-oxygen bond, with formation of a stable dilithium compound. Trapping of this intermediate with several electrophiles (alkyl halides, carbonyl derivatives, CO2) was successful. The extension of this procedure to several substituted phthalans (1b-i) was investigated, and the regiochemistry as well as the synthetic usefulness of these reactions are discussed.
- Azzena, Ugo,Demartis, Salvatore,Melloni, Giovanni
-
p. 4913 - 4919
(2007/10/03)
-
- 3,4-Dihydroisocoumarins from α-bromo-o-tolunitrile and ketones or aldehydes
-
o-Cyanobenzyllithium (3) was efficiently generated by lithium-tellurium exchange of the corresponding benzylic telluride 2 prepared in situ from lithium butanetellurolate and α-bromo-o-tolunitrile (1). Reaction of ketones or aldehydes with 3 afforded subs
- Kanda,Kato,Sugino,Kambe,Ogawa,Sonoda
-
p. 1102 - 1106
(2007/10/02)
-
- Acyl Cyanides as Carbonyl Heterodienophiles
-
Acyl cyanides have been shown to behave as carbonyl dienophiles in reactions with electron-rich o-quinodimethanes.This represents the first observation of an acyl cyanide carbonyl group reacting in such a manner.
- Connors, Richard,Durst, Tony
-
p. 7277 - 7280
(2007/10/02)
-
- Reactions of dianions derived from o-toluic acids: Facile synthesis of 3-phenyl-3,4-dihydroisocoumarins and 8-oxotetrahydroprotoberberines
-
o-Toluic acids have been dideprotonated by treatment with LDA or n-butyllithium in THF at -78 deg C.The obtained dianions heve been reacted with aromatic aldehydes and 3,4-dihydroisoquinolines to get dihydroisocoumarins and 8-oxotetrahydroberberines, respectively.
- Kessar, S V,Gupta, Y P,Singh, Surat
-
p. 721 - 722
(2007/10/02)
-
- Directed Lithiation of Tertiary β-Amino Benzamides
-
The directed ortho-lithiation-alkylation of several tertiary β-amino benzamides was studied.The ortho-substituted β-amino benzamides were hydrolyzed directly with 6 N hydrochloric acid, or by a three-step, one-pot reaction involving methylation, elimination, and treatment with aqueous acid. o-Toluic acid, 2-n-butylbenzoic acid, 2-methoxy-6-methylbenzoic aicd, and 4-methoxy-2-methylbenzoic acid were prepared by using this ortho-metalation-hydrolysis methodology.Ortho-lithiation and reaction with benzaldehyde or dimethylformamide followed by hydrolysis with aqueous acid gave lactones in good yield.Methanolysis of N-(4-methoxy-2-methyl benzoyl)-N'-methylpiperizine with sulfuric acid/methanol gave methyl 4-methoxy-2-methylbenzoate in 71percent yield.The conversion of tertiary benzamides into ketones and aldehydes was examined.Treatment of certain tertiary benzamides with alkyllithium reagents gave ketones, while reaction with a modified aluminum hydride reagent gave aldehydes
- Comins, Daniel L.,Brown, Jack D.
-
p. 3566 - 3572
(2007/10/02)
-
- Facile Generation and Trapping of α-Oxo-o-quinodimethane; a Synthesis of 3-Aryl-3,4-dihydroisocoumarins
-
Treatment of o-(trimethylsilylmethyl)benzoyl chloride (1) with fluoride ions in the presence of aromatic aldehydes and alkyl fumarates gives 3-aryl-3,4-dihydroisocoumarins (3) and substituted α-tetralones (4), respectively.
- Kessar, Satinder V.,Singh, Paramjit,Venugopal, D.
-
p. 1258 - 1259
(2007/10/02)
-
- THERMAL ADDITION REACTIONS TO BENZOCYCLOBUTENONES STUDIED BY FLASH PHOTOLYSIS
-
Ortho-quinoid vinylketenes 2 have been generated thruogh flash photolysis of benzocyclobutenones 1.A kinetic study of intermolecular addition reactions of 2 competing with the recyclization 2 -> 1 reveals strikingly different substituent effects for the addition of methanol and of dienophiles.
- Schiess, P.,Eberle, M.,Huys-Francotte, M.,Wirz, J.
-
p. 2201 - 2204
(2007/10/02)
-
- Ortho-Lithiated Tertiary Benzamides. Chain Extension via o-Toluamide Anion and General Synthesis of Isocoumarins Including Hydrangenol and Phyllodulcin
-
Lithiation of N,N-diethyl-2-methylbenzamide (2a) followed by condensation with aromatic aldehydes and basic hydrolysis leads to 3-aryl-3,4-dihydroisocoumarins 4 in modest overall yields.Adoption of this methodology to N,N-dimethyl-2-methyl-6-methoxybenzamide (7b) provides isocoumarins 9a and 9b which by selective demethylation procedures yields hydrangenol (10a) and phyllodulcin (10c), naturally occurring isocoumarins of pharmacological interest.A one-pot, abbreviated procedure for the preparation of both 9a and 9b starting with N,N-Dimethyl-2-methoxybenzamide (6c) is also described.
- Watanabe, Mitsuaki,Sahara, Masanori,Kubo, Masaki,Furukawa, Sunao,Billedeau, R. J.,Snieckus, V.
-
p. 742 - 747
(2007/10/02)
-
- Synthetic Application of Lithiation Reaction: Part XVIII - Synthesis of (+/-)-3,4-Dihydro-3-phenylisocoumarin and Aglycone of (+/-)-Dihydrohomalicine
-
N-Methylbenzamide on lithiation with n-butyllithium followed by reaction with N-methylformanilide gives compound (1), which on hydrolysis with dil.HCl furnishes 2-formylbenzoic acid (2).This acid on reaction with benzylidenetriphenylphosphorane gives stil
- Narasimhan, N. S.,Mali, R. S.,Kulkarni, B. K.
-
p. 850 - 852
(2007/10/02)
-
- Lactonization of o-Arylethenylbenzoic Acids: Formation of 3,4-Dihydro-1H-2-benzopyran-1-ones and Isobenzofuran-1(3H)-ones
-
The formation of six 3,4-dihydro-1H-2-benzopyran-1-ones (2a-f) and one isobenzofuran-1(3H)-one (3a) from o-arylethenylbenzoic acids (1) in neutral or acid solution is described.The benzoic acids having a neutral or electron-releasing group on the double bond give δ-lactones (2), whereas compounds with a strong electron-withdrawing group give the γ-lactones (3).The mechanism is discussed in terms of electronic effects.The rate of cyclization of the (Z)-compound is found to be faster than that of the (E)-compound.
- Teitei, Tsutomu
-
p. 1231 - 1235
(2007/10/02)
-
- Formation od some 3-Aryl-3,4-dihydroisocoumarins by Thermal Ring Closure of Stilbene-2-carboxylic Acids
-
When heated at 200 deg C, cis- and trans-4'- and 2'-methoxystilbene-2-carboxylic acids have been converted into the title compounds in varying yields, as has trans-4'-hydroxystilbene-2-carboxylic acid.On the other hand, trans-4'-nitrostilbene-2-carboxylic acid affords 3-(4-nitrobenzyl)phthalide.Mass spectrometry provides a simple method of distinguishing between the dihydroisocoumarins and phthalides.
- Bellinger, Geoffrey C. A.,Campbell, William E.,Giles, Robin G. F.,Tobias, Julius D.
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p. 2819 - 2826
(2007/10/02)
-
- Organic Tellurium and Selenium Chemistry. Reduction of Tellurides, Selenides, and Selenoacetals with Triphenyltin Hydride
-
Preparative and mechanistic details are described for the conversion of selenides into hydrocarbons RH> by heating with triphenyltin hydride at about 120 deg C.The process has been extended to selenoacetals in a form that constitutes a reduction methods for carbonyl compounds RR'C(SePh)2 -> RR'CH2>.Selective reduction of selenoacetals in the presence of thioacetals is possible.Cold-labeled species can be prepared by using triphenyltin deuteride.Tellurides are available easily without problems arising from exposure to air provided that the work is done in a photographic darkroom equipped with a red safety light.These tellurides, as well as the corresponding dichlorides , are reduced under very mild conditions (25-80 deg C) by triphenyltin hydride.The selenium- and tellurium-based chemistry has been used for the unusual process of reducing an epoxide in the presence of a ketone carbonyl.
- Clive, Derrick L. J.,Chittattu, Gim J.,Farina, Vittorio,Kiel, William A.,Menchen, Steven M.,et al.
-
p. 4438 - 4447
(2007/10/02)
-
- Cyclofunctionalisation of unsaturated acids with benzeneselenenyl chloride. Kinetic and thermodynamic aspects of the rules for ring closure
-
Experimental procedures are described for the synthetically useful reaction by which olefinic acids are converted into lactones carrying a benzeneseleno-group. Data are presented to define some of the mechanistic details of this type of cyclofunctionalisation and kinetic and thermodynamic factors relevant to the Rules for Ring Closure are discussed. A nomenclature is introduced for a treatment of ring-fusion stereochemistry.
- Clive, Derrick L.J.,Russell, Charles G.,Chittattu, Gim,Singh, Alok
-
p. 1399 - 1408
(2007/10/02)
-