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Akihiko Ishii - One of the best experts on this subject based on the ideXlab platform.
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π-Face-selective hetero Diels-Alder reactions of 3,4-di-tert-butylthiophene 1-oxide. An excellent trapping reagent for Thioaldehydes and thioketones
Tetrahedron Letters, 2003Co-Authors: Jun Takayama, Seiko Fukuda, Yoshiaki Sugihara, Akihiko Ishii, Juzo NakayamaAbstract:Hetero Diels–Alder reactions of 3,4-di- tert -butylthiophene 1-oxide ( 1 ) with Thioaldehydes and thioketones take place exclusively, except the reaction with thiobenzophenone, at the syn -π-face of 1 with respect to the SO bond. The π-face selectivity was explained in terms of the extent of conformational changes of 1 that are brought about in the process to the transition states.
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π-Face-selective hetero Diels–Alder reactions of 3,4-di-tert-butylthiophene 1-oxide. An excellent trapping reagent for Thioaldehydes and thioketones
Tetrahedron Letters, 2003Co-Authors: Jun Takayama, Seiko Fukuda, Yoshiaki Sugihara, Akihiko Ishii, Juzo NakayamaAbstract:Hetero Diels–Alder reactions of 3,4-di- tert -butylthiophene 1-oxide ( 1 ) with Thioaldehydes and thioketones take place exclusively, except the reaction with thiobenzophenone, at the syn -π-face of 1 with respect to the SO bond. The π-face selectivity was explained in terms of the extent of conformational changes of 1 that are brought about in the process to the transition states.
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synthesis structure and some reactions of 2 4 6 tri t butyl thiobenzaldehyde the first stable aromatic Thioaldehyde
Bulletin of the Chemical Society of Japan, 1996Co-Authors: Akihiko Ishii, Naoki Inamoto, Naoko Kumon, Takashi Ishida, Nobuo Fukuda, Hiroyuki Oyama, Fujiko Iwasaki, Renji OkazakiAbstract:The title compound 1 was synthesized by the reaction of 2,4,6-tri-t-butylphenyllithium with O-ethyl thioformate or that of 2,4,6-tri-t-butylbenzaldehyde hydrazone with disulfur dichloride in the presence of triethylamine. The Thioaldehyde 1 is a purple crystalline compound which is thermally quite stable; only around 200 °C it underwent intramolecular cyclization to give 6,8-di-t-butyl-3,4-dihydro-4,4-dimethyl-1H-2-benzothiopyran 9. The X-ray crystallographic analysis of 1 revealed that the thioformyl group is almost perpendicular to the aromatic ring. The reaction of 1 with 1-cyano-1-methylethyl radicals afforded 9, while that with t-butyl radicals gave 1,3,5-tri-t-butyl-2-t-butylthiomethylbenzene and t-butyl 2,2-dimethyl-1-(1,3,5-tri-t-butylbicyclo[2.2.0]hexa-2,5-dien-2-yl)propyl sulfide in addition to 9. Some Grignard reagents and organolithiums reacted with 1 gave carbophilic, thiophilic, double addition products and some others depending on the kind of the organometallic reagents. Hydrazine and butyl...
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photoreaction of a stable Thioaldehyde 2 4 6 tri tert butylthiobenzaldehyde
Journal of The Chemical Society-perkin Transactions 1, 1991Co-Authors: Mauro A Cremonini, Akihiko Ishii, Lodovico Lunazzi, Giuseppe Placucci, Naoko Kumon, Takaguki Kawashima, Renji OkazakiAbstract:The photochemical reaction of the only isolable aromatic Thioaldehyde ArCHS (1; Ar = 2,4,6-tri-tert-butylphenyl) in alkaline medium yields ArCH2CH2Ar (2), ArCH2SCH2Ar (3), 6,8-di-tert-butyl-3,4-dihydro-4,4-dimethyl-1H-2-benzothiine (4) and ArMe (5). A radical mechanism which accounts for the formation of these compounds is proposed, mainly on the basis of the direct observation (EPR spectroscopy) of a number of radicals such as ArCHS˙–(A), ArCHCH2Ar (B), and ArCH2˙(D). Results of scrambling of deuterium atoms confirmed the structure of these radicals through interpretation of the corresponding EPR spectra.
Renji Okazaki - One of the best experts on this subject based on the ideXlab platform.
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Chapter 5 Chemistry of Thioaldehydes
Organosulfur Chemistry, 2007Co-Authors: Renji OkazakiAbstract:Publisher Summary This chapter discusses Thioaldehydes and classifies them as transient and stable. Transient or simple Thioaldehydes are so reactive and have such short life-times that their reactions are usually carried out with the Thioaldehydes generated in situ in the presence of trapping reagents. Most of these reactions are cycloadditions (the Diels-Alder reaction and 1,3-dipolar cycloaddition). In addition to chemical trapping, some transient Thioaldehydes can be detected by spectroscopic methods. Compounds having a thioformyl group are usually highly unstable and reactive. The thioamide, the thioesters, and their vinylogous and analogs are known to exist as isolable, stable species as a result of the mesomeric effect that decreases the double bond nature of the C–S bond and hence the instability of the molecule. The use of bulky substituents enables the isolation of the stable Thioaldehydes. The synthesis, structure, and reactivity of these stable Thioaldehydes are described in this chapter.
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cycloaddition and oxidation reactions of a stable Thioaldehyde 2 4 6 tri t butyl thiobenzaldehyde
Bulletin of the Chemical Society of Japan, 1996Co-Authors: Soichiro Watanabe, Toshio Yamamoto, Takayuki Kawashima, Naoki Inamoto, Renji OkazakiAbstract:The title Thioaldehyde 1 undergoes [4 + 2] cycloaddition with 2,3-dimethyl-1,3-butadiene at 160 °C and [3 + 2] cycloadditions with diphenylnitrilimine and mesitonitrile oxide at room temperature. The intermediary cycloadduct with mesitonitrile oxide undergoes cycloreversion to give 2,4,6-tri-t-butylbenzaldehyde and mesityl isothiocyanate as the final products. Oxidation of 1 with m-chloroperbenzoic acid (mCPBA) and dimethyldioxirane (9) gives a mixture of (E)- and (Z)-isomers of the corresponding S-oxides (sulfines), the former and the latter being kinetically and thermodynamically controlled products, respectively. Although both (E)- and (Z)-sulfines are not further oxidized by mCPBA, the (Z)-sulfine is oxidized with 9 to give 7-oxa-8-thia-2,4,6-tri-t-butylbicyclo[4.3.0]nona-2,4,9-triene 8,8-dioxide and 6,8-di-t-butyl-3,4-dihydro-4,4-dimethyl-1H-2-benzothiopyran 2,2-dioxide, both of which are intramolecular cyclization products of an intermediary Thioaldehyde dioxide (sulfene).
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synthesis structure and some reactions of 2 4 6 tri t butyl thiobenzaldehyde the first stable aromatic Thioaldehyde
Bulletin of the Chemical Society of Japan, 1996Co-Authors: Akihiko Ishii, Naoki Inamoto, Naoko Kumon, Takashi Ishida, Nobuo Fukuda, Hiroyuki Oyama, Fujiko Iwasaki, Renji OkazakiAbstract:The title compound 1 was synthesized by the reaction of 2,4,6-tri-t-butylphenyllithium with O-ethyl thioformate or that of 2,4,6-tri-t-butylbenzaldehyde hydrazone with disulfur dichloride in the presence of triethylamine. The Thioaldehyde 1 is a purple crystalline compound which is thermally quite stable; only around 200 °C it underwent intramolecular cyclization to give 6,8-di-t-butyl-3,4-dihydro-4,4-dimethyl-1H-2-benzothiopyran 9. The X-ray crystallographic analysis of 1 revealed that the thioformyl group is almost perpendicular to the aromatic ring. The reaction of 1 with 1-cyano-1-methylethyl radicals afforded 9, while that with t-butyl radicals gave 1,3,5-tri-t-butyl-2-t-butylthiomethylbenzene and t-butyl 2,2-dimethyl-1-(1,3,5-tri-t-butylbicyclo[2.2.0]hexa-2,5-dien-2-yl)propyl sulfide in addition to 9. Some Grignard reagents and organolithiums reacted with 1 gave carbophilic, thiophilic, double addition products and some others depending on the kind of the organometallic reagents. Hydrazine and butyl...
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photoreaction of a stable Thioaldehyde 2 4 6 tri tert butylthiobenzaldehyde
Journal of The Chemical Society-perkin Transactions 1, 1991Co-Authors: Mauro A Cremonini, Akihiko Ishii, Lodovico Lunazzi, Giuseppe Placucci, Naoko Kumon, Takaguki Kawashima, Renji OkazakiAbstract:The photochemical reaction of the only isolable aromatic Thioaldehyde ArCHS (1; Ar = 2,4,6-tri-tert-butylphenyl) in alkaline medium yields ArCH2CH2Ar (2), ArCH2SCH2Ar (3), 6,8-di-tert-butyl-3,4-dihydro-4,4-dimethyl-1H-2-benzothiine (4) and ArMe (5). A radical mechanism which accounts for the formation of these compounds is proposed, mainly on the basis of the direct observation (EPR spectroscopy) of a number of radicals such as ArCHS˙–(A), ArCHCH2Ar (B), and ArCH2˙(D). Results of scrambling of deuterium atoms confirmed the structure of these radicals through interpretation of the corresponding EPR spectra.
P Zani - One of the best experts on this subject based on the ideXlab platform.
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thermal and lewis acid induced cycloaddition of Thioaldehyde s oxide monosubstituted sulfines to dienes iii
Journal of Organic Chemistry, 1991Co-Authors: G Barbaro, G Maccagnani, Arturo Battaglia, P Giorgianni, B F Bonini, P ZaniAbstract:The stereochemical course of the 1,4-cycloaddition of Thioaldehyde S-oxides (monosubstituted sulfines) to 2,3-dimethylbuta-1,3-diene, buta-1,3-diene, and cis- and trans-penta-1,3-diene was investigated. Unexpectedly, the reactions of buta-1,3-diene and 2,3-dimethylbuta-1,3-diene with Z-monoaryl sulfines afforded cis/trans mixtures of the corresponding dihydrothiopyran S-oxides, in which the relative amounts of the two isomers depended upon the initial diene/sulfine ratio. A Z to E isomerization of the dienophiles during the cycloaddition was responsible. On the other hand, Z/E mixtures of aliphatic tert-butyl sulfine gave, with 2,3-dimethylbuta-1,3-diene, only the corresponding trans cycloadduct. Catalysis of the reaction by Lewis acids, heretofore largely unexplored, was also investigated
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Thioaldehyde s oxide monosubstituted sulfines from thioacylsilane s oxides synthesis and fluorine and acid induced z e isomerization 2
Journal of Organic Chemistry, 1990Co-Authors: G Barbaro, G Maccagnani, Arturo Battaglia, P Giorgianni, B F Bonini, P ZaniAbstract:Aromatic and aliphatic, not enethiolizable, Thioaldehyde S-oxides (monosubstituted sulfines) are obtained from stereospecific fluorodesilylation of the corresponding thioacylsilane S-oxides with retention of configuration. A detailed investigation on the mechanism of the desilylation, as well as of the acid and fluoride ion induced Z/E interconversion has been performed
Christopher Barner-kowollik - One of the best experts on this subject based on the ideXlab platform.
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Polymer surface patterning via Diels-Alder trapping of photo-generated Thioaldehydes
2020Co-Authors: Mathias Glassner, Kim K. Oehlenschlaeger, Alexander Welle, Michael Bruns, Christopher Barner-kowollikAbstract:An efficient method for polymer surface patterning via Diels-Alder trapping of photo-generated Thioaldehydes is presented. It is demonstrated that Thioaldehyde end-groups generated by photolysis of phenacyl sulfides can be quantitatively trapped with various dienes. Poly(ethylene glycol) is immobilized on a surface in a spatially controlled fashion via irradiation through a shadow mask. © 2013 The Royal Society of Chemistry.
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Spatially controlled surface immobilization of nucleophiles via trapping of photo-generated Thioaldehydes
2020Co-Authors: Thomas Pauloehrl, Kim K. Oehlenschlaeger, Alexander Welle, Christopher Barner-kowollikAbstract:A novel and very simple photochemical strategy that utilizes light as a facile means to provide spatio-temporal control for the direct covalent immobilization of nucleophiles is presented. The concept is based upon the efficient trapping of photogenerated Thioaldehydes by amines, hydroxylamines, and thiols. Surface patterns of polymers and small molecules bearing pendant amine-, hydroxylamine- or thiol moieties were successfully generated and imaged in a time-of-flight secondary-ion mass spectrometry (ToF-SIMS) investigation. © 2013 The Royal Society of Chemistry.
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Pyreneacyl sulfides as a visible light-induced versatile ligation platform
Chemical Communications, 2017Co-Authors: Bryan T. Tuten, Jan Philipp Menzel, Kai Pahnke, James P. Blinco, Christopher Barner-kowollikAbstract:We report a visible light responsive moiety capable of generating highly reactive Thioaldehydes. Upon irradiation with visible light (420 nm) the pyreneacyl sulfide species undergoes a Norrish II elimination yielding Thioaldehydes capable of being trapped by nucleophiles (amines, aminoxys, and thiols), as well as Diels–Alder processes, representing a new versatile ligation platform.
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Photo‐Induced Functionalization of Spherical and Planar Surfaces via Caged Thioaldehyde End‐Functional Polymers
Advanced Functional Materials, 2014Co-Authors: Michael Kaupp, Alexander Welle, Alexander S Quick, Vanessa Trouillet, Martin Wegener, Cesar Rodriguez-emmenegger, Ognen Pop-georgievski, Christopher Barner-kowollikAbstract:The synthesis and application of a novel reversible addition-fragmentation chain transfer (RAFT) agent carrying a photocaged Thioaldehyde moiety is described (λmax = 355 nm). RAFT polymerization of styrene, dimethylacrylamide and a glycomonomer is evidenced (3600 g mol-1 ≤ Mn ≤ 15 000 g mol-1; 1.07 ≤ D{stroke} ≤ 1.20) with excellent end-group fidelity. The photogenerated Thioaldehyde on the chain ends can undergo hetero Diels-Alder reactions with dienes as well as reactions with nucleophiles. The terminal photoreactive polymers are photografted to porous diene-reactive polymeric microspheres. The grafted particles are in-depth characterized via scanning electron microscopy, elemental analysis, X-ray photoelectron spectroscopy, and high resolution FT-IR microscopy, leading to a qualitative as well as quantitative image of the core-shell objects. Grafting densities up to 0.10 molecules nm-2 are reached. The versatility of the Thioaldehyde ligation is evidenced by spatially resolved grafting of polystyrene onto nucleophilic groups present in poly (dopamine) (PDA)-coated glass slides and silicon wafers via two-photon direct laser writing (DLW) imaged by ToF-SIMS. The combination of Thioaldehyde ligation, RAFT polymerization, and DLW allows for the spatially resolved grafting of a vast range of polymers onto various substrates in any desired pattern with sub-micrometer resolution. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Spatially controlled surface immobilization of nucleophiles via trapping of photo-generated Thioaldehydes
Chemical Science, 2013Co-Authors: Thomas Pauloehrl, Kim K. Oehlenschlaeger, Alexander Welle, Christopher Barner-kowollikAbstract:A novel and very simple photochemical strategy that utilizes light as a facile means to provide spatio-temporal control for the direct covalent immobilization of nucleophiles is presented. The concept is based upon the efficient trapping of photogenerated Thioaldehydes by amines, hydroxylamines, and thiols. Surface patterns of polymers and small molecules bearing pendant amine-, hydroxylamine- or thiol moieties were successfully generated and imaged in a time-of-flight secondary-ion mass spectrometry (ToF-SIMS) investigation.
Juzo Nakayama - One of the best experts on this subject based on the ideXlab platform.
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π-Face-selective hetero Diels-Alder reactions of 3,4-di-tert-butylthiophene 1-oxide. An excellent trapping reagent for Thioaldehydes and thioketones
Tetrahedron Letters, 2003Co-Authors: Jun Takayama, Seiko Fukuda, Yoshiaki Sugihara, Akihiko Ishii, Juzo NakayamaAbstract:Hetero Diels–Alder reactions of 3,4-di- tert -butylthiophene 1-oxide ( 1 ) with Thioaldehydes and thioketones take place exclusively, except the reaction with thiobenzophenone, at the syn -π-face of 1 with respect to the SO bond. The π-face selectivity was explained in terms of the extent of conformational changes of 1 that are brought about in the process to the transition states.
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π-Face-selective hetero Diels–Alder reactions of 3,4-di-tert-butylthiophene 1-oxide. An excellent trapping reagent for Thioaldehydes and thioketones
Tetrahedron Letters, 2003Co-Authors: Jun Takayama, Seiko Fukuda, Yoshiaki Sugihara, Akihiko Ishii, Juzo NakayamaAbstract:Hetero Diels–Alder reactions of 3,4-di- tert -butylthiophene 1-oxide ( 1 ) with Thioaldehydes and thioketones take place exclusively, except the reaction with thiobenzophenone, at the syn -π-face of 1 with respect to the SO bond. The π-face selectivity was explained in terms of the extent of conformational changes of 1 that are brought about in the process to the transition states.
