- Oxygen-to-Oxygen Silyl Migration of α-Siloxy Sulfoxides and Oxidation-Triggered Allicin Formation
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Oxidation of α-siloxy thioethers leads to the formation of the corresponding sulfoxides as unstable intermediates, which undergo an intramolecular oxygen-to-oxygen silyl migration to break the C-S linkage. This process produces silyl protected sulfenic acids and subsequently thiosulfinates. It was used to develop oxidation-triggered allicin donors.
- Kelly, Shane S.,Shen, Tun-Li,Xian, Ming
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supporting information
p. 3741 - 3745
(2021/05/10)
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- Direct Substitution of Secondary and Tertiary Alcohols to Generate Sulfones under Catalyst- and Additive-Free Conditions
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An environmentally benign protocol that affords propargylic sulfones containing highly congested carbon centers from easily accessible alcohols and sulfinic acids with water as the only byproduct is reported. The reaction proceeded via an in situ dehydrative cross-coupling process by taking advantage of the synergetic actions of multiple hydrogen bonds rather than relying on an external catalyst and/or additives to achieve high product distribution.
- Liu, Yanan,Xie, Peizhong,Sun, Zuolian,Wo, Xiangyang,Gao, Cuiqing,Fu, Weishan,Loh, Teck-Peng
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supporting information
p. 5353 - 5356
(2018/09/13)
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- Palladium-catalyzed desulfitative heck-type reaction of aryl sulfinic acids with alkenes
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An efficient protocol has been developed for the desulfitative Heck-type reaction of aryl sulfinic acids with a variety of alkenes in the presence of a catalytic amount of Pd(OAc)2 and inexpensive Cu(OAc)2 as oxidant. This method does not require a ligand or a base, thereby broadening the scope of Pd-catalyzed coupling reactions. Copyright
- Wang, Guan-Wu,Miao, Tao
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supporting information; experimental part
p. 5787 - 5790
(2011/06/23)
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- The reaction of mercaptans with dimethyldioxirane. A facile synthesis of alkanesulfinic acids
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Dimethyldioxirae oxidizes aliphatic thiols to sulfinic acids in very good yield. Benzylic and aromatic thiols give a variety of other oxidation products using DMD.
- Gu,Harpp
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- Formation of Elusive vic-Disulfoxides and OS-Sulfenyl Sulfinates during the m-Chloroperoxybenzoic Acid (MCPBA) Oxidation of Alkyl Aryl Disulfides and Their Regioisomeric Sulfinothioic Acid S-Esters
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The initial step in the 1 equiv m-chloroperoxybenzonic acid (MCPBA) oxidation of 2,2-dimethylpropyl phenyl disulfide (10) and phenyl phenylmethyl disulfide (14) occurs predominantly at the sulfur atom bonded to the alkyl group to give S-phenyl 2,2-dimethylpropanesulfinothioate (5) and S-phenyl phenylmethanesulfinothioate (6), respectively.The 2 equiv MCPBA oxidation of disulfide 10 gives S-phenyl 2,2-dimethylpropanesulfonothioate (23) as the major product.The 1 equiv MCPBA oxidation of thiosulfinates 5 and 6 and S-2,2-dimethylpropyl benzenesulfinothioate (9) ultimately gives thiosulfonate 23, S-phenyl phenylmethanesulfonothioate (17), and thiosulfonate 23, respectively, as the major products.Thus, peroxidation of regioisomeric S-alkyl and S-aryl sulfinothioates 5 and 9 occurs predominantly at the sunfenyl sulfur atom to give diastereomeric vic-disulfoxides (α-disulfoxides) which may undergo cycloelimination to sulfines and sulfenic acids, dissociate to sulfinyl radicals, and rearrange intramoleculary to OS-sulfenyl silfinates and/or to sulfonothioic acid S-esters.OS-Sulfenyl sulfinates may isomerize to sulfonothioic acid S-esters or dissociate to sulfinyl radicals and/or to thiyl and sulfonyl radicals.The sulfinyl radicals may combine to form vic-disulfoxides and/or OS-sulfenyl sulfinates while the thiyl and sulfonyl radicals may lead to sulfonothioic acid S-esters.
- Freeman, Fillmore,Angeletakis, Christos N.
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p. 793 - 798
(2007/10/02)
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- Formation of α-Disulfoxides, Sulfinic Anhydrides, and Sulfines during the m-Chloroperoxybenzoic Acid Oxidation of Symmetrical S-Alkyl Alkanethiosulfinates
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The m-chloroperoxybenzoic acid (MCPBA) oxidation of S-methyl methanethiosulfinate (33), S-propyl propanethiosulfinate (34), S-2-propyl 2-propanethiosulfinate (35), S-butyl butanethiosulfinate (36), and S-(phenylmethyl)phenylmethanethiosulfinate (37) has been at low temperatures and compared with the MCPBA oxidation of S-(2-methyl-2-propyl)-2-methyl-2-propanethiosulfinate (26) and S-(2,2-dimethylpropyl)-2,2-dimethylpropanethiosulfinate (30).Diastereomeric α-disulfoxides are observed with 33-36 at -40 deg C, sulfinic anhydrides are observed with 33, 35, and 36 at -40 deg C, and sulfines are observed on warming the product mixtures from 34-37 from -40 deg C to -20 deg C.The lachrymatory factor ((Z)-propanethial S-oxide, 47) of the onion was observed during the oxidation of 35.The absence of thiosulfonates at -40 deg C and their presence at higher temperature suggest that they are not formed in the initial oxidation process but from subsequent reactions of thiosulfinates and sulfinic acids.Various mechanisms for the formation of intermediates and products are discussed.
- Freeman, Fillmore,Angeletakis, Christos N.
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p. 4039 - 4049
(2007/10/02)
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- Intermediates in the Peroxy Acid Oxidation of Phenyl Phenylmethanethiosulfinate
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The m-chloroperoxybenzoic acid (MCPBA) oxidation of phenyl phenylmethanethiosulfinate (9) in CDCl3 has been studied.Low-temperature 1H NMR and 13C NMR spectra show that phenyl phenylmethanethiosulfonate (7), phenylmethanesulfonic acid (26), and phenylmethanesulfinic acid (27) are formed during the early stages of oxidation.Although 7 may be formed via direct attack of MCPBA at the sulfinyl sulfur atom of 9, the presence of 7, 26, and 27 is also explicable in terms of formation and rearrangement of metastable α-disulfoxide (13) and sulfenyl sulfinate (14) intermediates.
- Freeman, Fillmore,Angeletakis, Christos N.
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p. 3991 - 3996
(2007/10/02)
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- Unexpected Behavior of an α-Tosyloxy Sulfone Compared with an α-Chloro Sulfone in Base-Induced Reactions
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Unexpectedly, a rate ratio for kOTs/kCl of 0.0011 was observed in 1,3-eliminations of (tosyloxy)methyl benzyl sulfone and chloromethyl benzyl sulfone in t-BuOK/t-BuOH (25 deg C), while in MeONa/MeOH (25 deg C) neither 1,3-elimination occurred; instead, the α-tosyloxy sulfone underwent facile S-O cleavage to provide methyl p-toluenesulfonate and α-toluenesulfinic acid.
- Meyers, Cal Y.,Hua, Duy H.,Peacock, Nancy J.
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p. 1719 - 1721
(2007/10/02)
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- Primary Processes in the Reaction of OH-Radicals with Sulphoxides
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The primary processes in the OH radical-induced oxidation mechanism of sulphoxides have been investigated by pulse radiolysis and, in particular, by an improved conductivity detection method with time resolution of ca. 50 ns in aqueous solution.Electrophilic addition of the OH radical to the sulphoxide group leads to a transient adduct, R2SO(OH) which decays unimolecularly with t0.5 up to 100 ns into a sulphinic acid, RSO2H, and a radical R.The various RSO2H have been identified by their pKa, and R (including t-butyl and phenyl radicals) by direct optical measurement or chemical scavenging experiments.The probability of radical split off from R2SO(OH) for mixed sulphoxides depends on the stability of the radical leaving.Depending on the nature of the sulphoxide substituents two other OH radical reactions compete with, and may even predominate over, the addition at the sulphoxide group.Thus hydrogen-atom abstraction readily occurs from longer chain and branched aliphatic groups and in the presence of aromatic substituents OH radicals add to the ?-system to form a hydroxycyclohexadienyl radical.The respective yields, kinetics and some physico-chemical properties of the primary species are presented and discussed.
- Veltwisch, Dieter,Janata, Eberhard,Asmus, Klaus-Dieter
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p. 146 - 153
(2007/10/02)
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