- The Formation of Vinyl Sulfides by the Cleavage of the Carbon-Sulfur Bond in Dithioacetals with CuCl2
-
The elimination of arene- and alkanethiol from diaryl and dialkyl dithioacetals, in the presence of copper(I) or copper(II) salt plus tertiary amine, to produce the corresponding aryl and alkyl vinyl sulfides, respectively, has been studied.The employment of a combination of 2 mol equiv. of CuCl2 and 2 mol equiv. of N,N-diisopropylethylamine is most favorable.
- Oida, Tatsuo,Tanimoto, Shigeo,Ikehira, Hideyuki,Okano, Masaya
-
-
Read Online
- Radical Cation Cycloadditions Using Cleavable Redox Auxiliaries
-
The incorporation of an easily oxidized arylsulfide moiety facilitates the photocatalytic generation of alkene radical cations that undergo a variety of cycloaddition reactions with electron-rich reaction partners. The sulfide moiety can subsequently be reductively cleaved in a traceless fashion, affording products that are not otherwise directly accessible using photoredox catalysis. This approach constitutes a novel oxidative “redox auxiliary” strategy that offers a practical means to circumvent a fundamental thermodynamic limitation facing photoredox reactions.
- Lin, Shishi,Lies, Shane D.,Gravatt, Christopher S.,Yoon, Tehshik P.
-
supporting information
p. 368 - 371
(2017/04/21)
-
- Exploring chromium(III)-alkyl bond homolysis with CpCr[(ArNCMe) 2CH](R) complexes
-
A range of paramagnetic Cr(III) monohydrocarbyl complexes CpCr[(ArNCMe)2CH](R) (Ar = ortho-disubstituted aryl; R = primary alkyl, trimethylsilylmethyl, benzyl, phenyl, alkenyl, or alkynyl) were synthesized to investigate how varying the steric and electronic properties of the R group affected their propensity for Cr-R bond homolysis. Most complexes were prepared by salt metathesis of known CpCr[(ArNCMe)2CH](Cl) compounds in Et2O with commercial RMgCl solutions, although more sterically demanding combinations of Ar and R groups necessitated the use of halide-free MgR2 reagents and the Cr(III) tosylate or triflate derivatives. Alternative synthetic routes to Cr(III)-R species using the previously reported Cr(II) compounds CpCr[(ArNCMe)2CH] and sources of R? radicals (e.g., BEt3 and air) were also explored. The UV-vis spectra of the CpCr[(ArNCMe)2CH](R) complexes possessed two strong bands with maximum absorbances in the ranges 395-436 nm and 535-582 nm, with the band in the latter range being particularly characteristic of the Cr(III)-R compounds. The Cr-CH2R bond lengths as determined by single-crystal X-ray diffraction were longer than those in the corresponding Cr-CH3 complexes, typically falling in the range 2.10 to 2.13 A. The Cr(III) benzyl compounds displayed longer Cr-CH2Ph distances, while the bond lengths for the alkenyl and alkynyl species were substantially shorter. The rate of Cr-R bond homolysis at room temperature was determined by monitoring the reaction of Cr(III) neopentyl, benzyl, and isobutyl complexes with excess PhSSPh using UV-vis spectroscopy. Although the other primary alkyl, phenyl, and alkenyl compounds did not undergo appreciable homolysis under these conditions, they were cleanly converted to CpCr[(ArNCMe)2CH](SPh) by photolysis.
- MacLeod, K. Cory,Conway, Julia L.,Patrick, Brian O.,Smith, Kevin M.
-
scheme or table
p. 17325 - 17334
(2011/03/01)
-
- α-(Benzotriazolyl)methyl phenyl thioethers: Convenient reagents for α-phenylthioalkylation of silylated nucleophiles
-
Stable, crystalline α-(benzotriazolyl)methyl phenyl thioethers (1), easily prepared from carbonyl compounds, thiophenol and benzotriazole, are convenient reagents for the phenylthiomethylation of trimethylsilyl cyanide, trimethylallylsilane, and trimethyl
- Katritzky, Alan R.,Chen, Jie,Belyakov, Sergei A.
-
p. 6631 - 6634
(2007/10/03)
-
- First synthesis, X-ray structure analysis and reactions of alkenyltriphenylbismuthonium salts
-
Treatment of triphenylbismuth difluoride with alkenyltrimethylsilanes 1 or trimethylsilyl cyanidealkenyltrialkylstannanes 3 in the presence of boron trifluoride-diethyl ether gave the corresponding alkenyltriphenylbismuthonium tetrafluoroborates 2 in moderate to good yields. An X-ray crystallographic analysis of the salt 2e confirmed the distorted tetrahedral geometry of the central bismuth atom. When treated with a sulfinate 5 or the thiolate 11, the salts 2 readily transferred both the vinyl and phenyl moieties to these nucleophiles to afford the sulfones 7-10 or the sulfides 12, 13, respectively. In the presence of a palladium catalyst, the salt 2e underwent the Heck-type reaction with ethyl acrylate 17 to afford the dienoate 18 and cinnamate 19 in moderate yields. Action of KOBut on the salt 2b yielded p-tolylacetylene 22, while a similar reaction with the salt 2e in the presence of the styrenes 23 gave the cyclopropanes 24. A Hammett study of the latter reaction has suggested a possible involvement of an alkylidenecarbene as the intermediate in these base-promoted reactions.
- Matano, Yoshihiro,Yoshimune, Masanori,Azuma, Nagao,Suzuki, Hitomi
-
p. 1971 - 1977
(2007/10/03)
-
- Reactions of Sulfoxides with Magnesium Amides. Transformations of Sulfoxides into Sulfides, Dithioacetals and Vinyl Sulfides
-
The reactions of sulfoxides with magnesium amides generated in situ from the reaction of ethylmagnesium bromide and seconday amines, such as diisopropylamine (DIPA) or 2,2,6,6-tetramethylpiperidine (TMP) in diethyl ether, were examined.Diaryl sulfoxides were heated with the diisopropylaminomagnesium reagent in diethyl ether to give the corresponding diaryl sulfides in 42-52percent yields.Sulfoxides bearing hydrogens at the α-position only(RSOCH2R1) reacted with the tetramethylpiperidinomagnesium reagent at room temperature to produce the corresponding dithioacetals (RSCHR1SR) in 47-86percent yields.The treatment of sulfoxides bearing hydrogens both at the α-and β-positions (RSOCHR1CHR2R3) with the magnesium amides at room temperature afforded the corresponding vinyl sulfides (RSCR1=CR2R3) in 52-72percent yields accompanying 2.3-27percent yields of the corresponding dithioacetals.The pathways leading to the products involving the formation of the sulfur-stabilized carbonium ion intermediates are discussed.
- Kobayashi, Kazuhiro,Kawakita, Masataka,Yokota, Kouichi,Mannami, Tohru,Yamamoto, Koji,et al.
-
p. 1401 - 1408
(2007/10/02)
-
- The reaction of 1-chloro-2-methyl-2-propenyllithium with a selection of organolithiums. The development and synthetic utility of novel base/nucleophile combinations
-
The title compound was generated by and reacted with (1) a series of reagents which have basic as well as nucleophilic properties and (2) a series of base/nucleophile combinations.Product yields of the isobutenyl derivative were generally low to very good, and the best results (89percent) were obtained by using a 1:2 ratio (3 equiv total) of nBuLi:LiPPh2.Synthetic utility of the reaction is optimized as it approaches a situation in which the base/nucleophile combination is composed of one compound which is both a strong base and a poor nucleophile and another compound which is both a weak base and a good nucleophile.
- Nelson, Donna J.,Nagarajan, Ananthanarayanan
-
-
- SYNTHESIS OF 2-METHYLPROPENYL SULFIDES AND THEIR OXYGEN AND NITROGEN ANALOGS
-
Conditions were developed for the convinient preparative synthesis of 2-methylpropenyl sulfides and their oxygen and nitrogen analogs on the basis of reactions of thiols, alcohols, and lactams with isobutyraldehyde in excess of chlorotrimethylsilane.By-pr
- Turchaninova, L.P.,Shipov, A.G.,Korchevin, N.A.,Deryagina, E.N.,Baukov, Yu.I.,Voronkov, M.G.
-
p. 1889 - 1892
(2007/10/02)
-
- Stereoselective Additions of Nucleophilic Alkenes to Chiral Thionium Ions
-
A convenient one-pot process has been developed for conversion of an aldehyde to an arylthionium ion (e.g., Schemes IV and V), which can be trapped by a nucleophilic alkene.The stereochemistry of the reactions of such chiral and prochiral arylthionium ions with achiral and prochiral nucleophilic alkenes has been studied.The major adducts are those predicted by qualitative application of the Cram-Felkin rule.Quantitatively, however, the nature of the thionium aryl group has a marked effect.For example, whereas 12 reacts with the phenylthionium ion derived from 2-phenyl propanol to give keto sulfides 13a and 14a in a ratio of 4:1, the corresponding reaction of the mesitylthionium ion affords the analogous keto sulfides 24a and 25a in a ratio of > 98:2.In reactions between prochiral thionium ions and prochiral enol silanes, good simple (anti) relative stereochemistry is observed, especially with enol silane 35 (Scheme VII, Table IV).Mesitylthionium ions of α-chiral aldehydes react with prochiral enol silanes to give one of the four possible products in predominance (Scheme VIII, Table V).Again, however, enol silane 35 is found to be a superior reagent, giving 41 in 97percent stereoisomeric purity.The α-methyl-β-arylthio ketones produced in these thionium ion reactions can be transformed by a straightforward process, which includes desulfurization, into chain compounds having anti 1,3-dimethyl branches (e.g., Scheme IX).An iterative application of this scheme can be used to prepare deoxypolypropionate structures, as shown in Scheme X.
- Mori, Ichiro,Bartlett, Paul A.,Heathcock, Clayton H.
-
p. 5966 - 5977
(2007/10/02)
-
- Synthesis of Alkenes via Peterson Reaction
-
The α-phenylthiosilanes (2) have been used to prepare the α-silyl anions (1) by reaction with lithium naphthalenide; subsequent condensation with a carbonyl compound gave the alkene (8) via the Peterson reaction.The α-phenylthiosilanes (2) were prepared from n,n-bis(phenylthio)acetals (4) by reaction with lithium naphthalenide and chlorotrimethylsilane.The n,n-bis(phenylthio)acetals (4) were obtained, in turn, from 1,1-bis(phenylthio)acetals (5) by anion formation with butyl-lithium-N,N,N',N'-tetramethylethylenediamine complex in hexane followed by reaction with an alkyl halide.The Peterson reaction was also used to prepare vinyl sulphides (9) and vinyl sulphones (13).
- Ager, David J.
-
p. 183 - 194
(2007/10/02)
-
- BENZYNE-INDUCED RING OPENING REACTION OF THIIRANES. EFFICIENT SYNTHESIS OF PHENYL VINYL SULFIDES
-
A series of thiiranes react with benzyne to provide an efficient synthesis of phenyl vinyl sulfides.The reaction is stereospecific, thus producing cis-(phenylthio)-stilbene from cis-2,3-diphenylthiirane and trans-(phenylthio)stilbene from trans-2,3-diphen
- Nakayama, Juzo,Takeue, Satoshi,Hoshino, Masamatsu
-
p. 2679 - 2682
(2007/10/02)
-
- Ether substituted cyclopropanecarboxylic acids and esters
-
Novel esters of ether and thioether substituted cyclopropanecarboxylic acids, synthesis thereof, and intermediates therefor, such esters being useful as pesticides.
- -
-
-
- α-IODOSULFIDES
-
α-Iodosulfides are formed in high yield by the reaction of O-trimethylsilylhemithioacetals with iodotrimethylsilane.Elimination of HI by base these α-iodosulfides provides easy access to vinylsulfides.
- Aida, T.,Harp, David N.,Chan, T. H.
-
p. 3247 - 3250
(2007/10/02)
-