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Tsuyoshi Satoh - One of the best experts on this subject based on the ideXlab platform.
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synthesis of 2 azabicyclo 2 1 0 pentanes by the intramolecular nucleophilic substitution of cyclopropylmagnesium carbenoids with magnesium anilide
Tetrahedron, 2017Co-Authors: Tsutomu Kimura, Toshiki Nishimura, Natsumi Wada, Tsuyoshi SatohAbstract:Abstract A variety of 2-azabicyclo[2.1.0]pentanes were synthesized by the intramolecular nucleophilic substitution of cyclopropylmagnesium carbenoids with magnesium anilide. The 1-chlorocyclopropyl p -tolyl Sulfoxides possessing an N -aryl-substituted aminomethyl group were prepared from dichloromethyl p -tolyl Sulfoxide, α,β-unsaturated carboxylic acid esters, and anilines in four steps. The deprotonation of the amine with t -BuMgCl followed by Sulfoxide/magnesium exchange of the Sulfoxides with i -PrMgCl led to the generation of the cyclopropylmagnesium carbenoids possessing a magnesium anilide moiety. Subsequent intramolecular nucleophilic substitution of the cyclopropylmagnesium carbenoids occurred in a 4-exo-tet manner to give the 2-azabicyclo[2.1.0]pentanes. The optically active 2-azabicyclo[2.1.0]pentane was synthesized using a p -tolylsulfinyl group as a chiral auxiliary.
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degree of vinylidene character of α heteroatom substituted vinylmagnesium chlorides a dft study to discern the role of the halogen atom in magnesium alkylidene carbenoid chemistry
Tetrahedron, 2013Co-Authors: Tsutomu Kimura, Tsuyoshi SatohAbstract:Abstract DFT calculations were performed on a series of α-heteroatom-substituted vinylmagnesium chlorides, CH 2 CXMgCl·2(OMe 2 ) (X=NMe 2 , OMe, F, SMe, Cl, SeMe, and Br), at the B3LYP/6-311++G(d,p) level to elucidate the degree of vinylidene character of such species. α-Halo-substituted vinylmagnesium chlorides were found to have considerable vinylidene character. A donor–acceptor interaction between the C–Mg bonding orbital and the C–X antibonding orbital was responsible for the vinylidene character of α-heteroatom-substituted vinylmagnesium chlorides. A Sulfoxide/magnesium exchange reaction of 1-halovinyl phenyl Sulfoxides with i -PrMgCl was more exothermic than the exchange reaction of phenyl vinyl Sulfoxide with i -PrMgCl by 12.8–13.9 kcal/mol.
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efficient synthesis of cyclopropanecarboxylic acid esters starting from the conjugate addition of lithium ester enolates to 1 chlorovinyl p tolyl Sulfoxides
Synlett, 2013Co-Authors: Tsutomu Kimura, Hitoshi Momochi, Nobuhito Nakaya, Yoshiaki Hattori, Tsuyoshi SatohAbstract:An efficient synthesis of tert -butyl cyclopropanecarboxylates was achieved in three steps using 1-chlorovinyl p -tolyl Sulfoxides as key materials. The conjugate addition of lithium ester enolates to the Sulfoxides gave tert -butyl 4-chloro-4-( p -tolylsulfinyl)butanoates in high yield. The p -tolylsulfinyl group in the resultant adducts was then removed by the Sulfoxide–magnesium exchange reaction with i -PrMgCl at –60 °C. Cyclization of the desulfinylated products, tert -butyl 4-chlorobutanoates, took place in the presence of NaHMDS in a THF–DMPU mixture to afford tert -butyl cyclopropanecarboxylates in good yield. The asymmetric synthesis of both enantiomers of tert -butyl cyclopropanecarboxylate was successfully achieved using optically active ( E )- and ( Z )-Sulfoxides with high enantiomeric excesses.
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resolution of racemic aryl dichloromethyl Sulfoxides with menthone
Tetrahedron-asymmetry, 2009Co-Authors: Takafumi Noguchi, Toshifumi Miyagawa, Tsuyoshi SatohAbstract:Abstract The addition reaction of the sodium α-sulfinyl carbanion of a racemic aryl dichloromethyl Sulfoxide to (−)-menthone in the presence of boron trifluoride diethyl etherate gave an adduct as a mixture of two easily separable diastereomers. After separation of the diastereomers, they were each treated with sodium hydride to afford enantiomerically pure aryl dichloromethyl Sulfoxides and (−)-menthone both in high yields. This procedure provides a simple and efficient method for the resolution of racemic aryl dichloromethyl Sulfoxides.
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a Sulfoxide version of the julia lythgoe olefination a new method for the synthesis of olefins from carbonyl compounds and Sulfoxides with carbon carbon coupling
Tetrahedron, 2000Co-Authors: Tsuyoshi Satoh, Noriko Hanaki, Noriko Yamada, Tohru AsanoAbstract:Abstract Reaction of β-mesyloxy (or acetoxy) Sulfoxides, derived from alkyl (or arylmethyl) phenyl Sulfoxides and carbonyl compounds in two steps, with alkylmetals (n-BuLi, t-BuLi, or EtMgBr) at low temperature gave olefins in good to excellent yields. When the β-hydroxy Sulfoxides derived from arylaldehydes were treated with mesyl chloride in the presence of triethylamine, the Sulfoxides directly gave E-olefins in good yields. These reactions offer a Sulfoxide version of the Julia–Lythgoe olefination. The reductive vicinal elimination was found to take place through the direct Sulfoxide–metal exchange. The stereochemistry of the elimination was investigated and found to be stereospecific; however, the stereospecificity was found to be dependent on the substrates.
Carsten Bolm - One of the best experts on this subject based on the ideXlab platform.
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Sulfoxide to sulfilimine conversions use of modified burgess type reagents
Advanced Synthesis & Catalysis, 2013Co-Authors: Christine M M Hendriks, Philip Lamers, Julien Engel, Carsten BolmAbstract:Sulfoxides can directly be converted into N-cyanosulfilimines using a new Burgess-type reagent. By applying this strategy with a related reagent variant, synthetically valuable NH-sulfoximines have been prepared from Sulfoxides via N-protected sulfilimines. The practical three-step reaction sequence is generally high yielding and applicable to a wide range of substrates. The Sulfoxide-to-sulfilimine conversion can also be performed under solvent-reduced conditions in a ball mill.
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Sulfoxide‐to‐Sulfilimine Conversions: Use of Modified Burgess‐Type Reagents
Advanced Synthesis & Catalysis, 2013Co-Authors: Christine M M Hendriks, Philip Lamers, Julien Engel, Carsten BolmAbstract:Sulfoxides can directly be converted into N-cyanosulfilimines using a new Burgess-type reagent. By applying this strategy with a related reagent variant, synthetically valuable NH-sulfoximines have been prepared from Sulfoxides via N-protected sulfilimines. The practical three-step reaction sequence is generally high yielding and applicable to a wide range of substrates. The Sulfoxide-to-sulfilimine conversion can also be performed under solvent-reduced conditions in a ball mill.
Tohru Asano - One of the best experts on this subject based on the ideXlab platform.
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a Sulfoxide version of the julia lythgoe olefination a new method for the synthesis of olefins from carbonyl compounds and Sulfoxides with carbon carbon coupling
Tetrahedron, 2000Co-Authors: Tsuyoshi Satoh, Noriko Hanaki, Noriko Yamada, Tohru AsanoAbstract:Abstract Reaction of β-mesyloxy (or acetoxy) Sulfoxides, derived from alkyl (or arylmethyl) phenyl Sulfoxides and carbonyl compounds in two steps, with alkylmetals (n-BuLi, t-BuLi, or EtMgBr) at low temperature gave olefins in good to excellent yields. When the β-hydroxy Sulfoxides derived from arylaldehydes were treated with mesyl chloride in the presence of triethylamine, the Sulfoxides directly gave E-olefins in good yields. These reactions offer a Sulfoxide version of the Julia–Lythgoe olefination. The reductive vicinal elimination was found to take place through the direct Sulfoxide–metal exchange. The stereochemistry of the elimination was investigated and found to be stereospecific; however, the stereospecificity was found to be dependent on the substrates.
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A Sulfoxide Version of the Julia–Lythgoe Olefination: A New Method for the Synthesis of Olefins from Carbonyl Compounds and Sulfoxides with Carbon–Carbon Coupling
Tetrahedron, 2000Co-Authors: Tsuyoshi Satoh, Noriko Hanaki, Noriko Yamada, Tohru AsanoAbstract:Abstract Reaction of β-mesyloxy (or acetoxy) Sulfoxides, derived from alkyl (or arylmethyl) phenyl Sulfoxides and carbonyl compounds in two steps, with alkylmetals (n-BuLi, t-BuLi, or EtMgBr) at low temperature gave olefins in good to excellent yields. When the β-hydroxy Sulfoxides derived from arylaldehydes were treated with mesyl chloride in the presence of triethylamine, the Sulfoxides directly gave E-olefins in good yields. These reactions offer a Sulfoxide version of the Julia–Lythgoe olefination. The reductive vicinal elimination was found to take place through the direct Sulfoxide–metal exchange. The stereochemistry of the elimination was investigated and found to be stereospecific; however, the stereospecificity was found to be dependent on the substrates.
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ligand exchange reaction of Sulfoxides in organic synthesis Sulfoxide version of the julia lythgoe olefination
Tetrahedron Letters, 1998Co-Authors: Tsuyoshi Satoh, Noriko Yamada, Tohru AsanoAbstract:Abstract Reaction of β-mesyloxy Sulfoxides, derived from alkyl (or arylmethyl) phenyl Sulfoxides and aldehydes in two steps, with alkylmetal ( n -BuLi, t -BuLi, or EtMgBr) at −78 °C gave olefins in good to excellent yields. This reaction offers a Sulfoxide version of the Julia-Lythgoe olefination.
Dénes Szabó - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and hydrolysis of optically active naphthyl-phenyl-bis(acyloxy)spiro-λ4-sulfane: absolute configurations of spiro-λ4-sulfanes, related sulfonium salts and naphthyl phenyl Sulfoxides determined by CD spectroscopy using exciton chirality and
Tetrahedron-asymmetry, 2003Co-Authors: Jenő Varga, József Rábai, Ferenc Ruff, Árpád Kucsman, Elemér Vass, Miklós Hollósi, Dénes SzabóAbstract:Abstract ( S )-(+)- and ( R )-(−)-enantiomers of naphthyl-phenyl-bis(acyloxy)spiro-λ 4 -sulfane 2 were prepared from the precursors ( R )-(−)- and ( S )-(+)-naphthyl phenyl Sulfoxide dicarboxylic acid 2a with acetic anhydride. The hydrolysis of spiro-λ 4 -sulfane ( R )-(−)- 2 in acidic and basic solutions gave as major products Sulfoxide ( S )-(+)- 2a and ( R )-(−)- 2a , respectively. The selectivity of the reactions was interpreted with the different reactivities of the ortho and peri neighboring carboxylic groups of the Sulfoxide 2a , and with the different ability of the five and six-membered rings to be cleaved in spiro-λ 4 -sulfane 2 . The absolute configurations of the enantiomeric spiro-λ 4 -sulfanes 2 and Sulfoxides 2a were determined by CD spectroscopy. Exciton coupling was observed in the spectrum of spiro-λ 4 -sulfane 2 between the benzene 1 L a and naphthalene 1 B b transitions, which results in a negative couplet for ( R )-(−)- 2 . Exciton coupling can be expected only for the 1 B b transitions of the S -phenyl and S -naphthyl rings of the Sulfoxides, which define a positive couplet for ( S )-(+)- 2a . Empirical rules were found to be valid for the determination of configuration of spiro-λ 4 -sulfanes and related sulfonium compound derivatives with a trigonal bipyramidal structure, and for that of naphthyl-phenyl-Sulfoxides. Both spiro-λ 4 -sulfanes and Sulfoxides should be viewed from the side of the lone pair; the axial substituents in the former case and the downwards oriented SO bond in the latter case are placed in a vertical plane. Rings and substituents in the upper-right and lower-left sectors define positive exciton couplets, while the opposite case is characterized by negative exciton-coupled circular dichroism (EC-CD).
Dongding Chen - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of N-Alkylpyridin-4-ones and Thiazolo[3,2-a]pyridin-5-ones through Pummerer-Type Reactions.
The Journal of Organic Chemistry, 2019Co-Authors: Jingjia Huang, Dongding ChenAbstract:N-Alkylated 4-pyridones were obtained through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhydride-activated Sulfoxides and 4-fluoropyridine derivatives, followed by hydrolysis. On the other hand, triflic anhydride-activated benzyl 6-fluoro-2-pyridyl Sulfoxide could react with alkenes or alkynes to afford thiazolo[3,2-a]pyridin-5-ones, via the pyridinium salt intermediates.
