- Transition-metal-free decarboxylative thiolation of stable aliphatic carboxylates
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A transition-metal-free decarboxylative thiolation protocol is reported in which primary, secondary, tertiary (hetero)aryl acetates and α-CN substituted acetates undergo the decarboxylative thiolation smoothly, to deliver a variety of functionalized aryl alkyl sulfides in moderate to excellent yields. Aryl diselenides are also amenable substrates for construction of C-Se bonds under the simple and mild reaction conditions. Moreover, the protocol is successfully applied to the late-stage modification of pharmaceutical carboxylates with satisfactory chemoselectivity and functional-group compatibility. This journal is
- Xing, Wei-Long,Liu, De-Guang,Fu, Ming-Chen
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p. 4593 - 4597
(2021/02/03)
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- Alkyl Sulfides as Promising Sulfur Sources: Metal-Free Synthesis of Aryl Alkyl Sulfides and Dialkyl Sulfides by Transalkylation of Simple Sulfides with Alkyl Halides
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A site-selective metal-free dealkylative approach to synthesize aryl alkyl and symmetrical dialkyl sulfides has been developed. This procedure is convenient and has wide functional group tolerance giving rise to sulfides carrying various alkyl chains from simple alkyl sulfides and alkyl halides in good to excellent yields. This transalkylation proceeds by an ionic mechanism via sulfonium intermediates and it was proposed that dimethylacetamide (DMAC) may participate in part to promote the reaction.
- Liu, Ting,Qiu, Renhua,Zhu, Longzhi,Yin, Shuang-Feng,Au, Chak-Tong,Kambe, Nobuaki
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supporting information
p. 3833 - 3837
(2018/12/05)
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- Photosensitized oxidation of aryl benzyl sulfoxides. Evidence for nucleophilic assistance to the c-s bond cleavage of aryl benzyl sulfoxide radical cations
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The radical cations of a series of aryl benzyl sulfoxides (4-X-C6H4CH2SOC6H4Y+?) have been generated by photochemical oxidation of the parent sulfoxides sensitized by 3-cyano-N-methylquinolinium perchlorate (3-CN-NMQ+ClO4-). Steady-state photolysis experiments showed the prevailing formation of benzylic products deriving from the C-S fragmentation in the radical cations, together with sulfur-containing products. Formation of sulfoxide radical cations was unequivocally established by laser flash photolysis experiments showing the absorption bands of 3-CN-NMQ? (λmax = 390 nm) and of the radical cations (λmax = 500-620 nm). The decay rate constants of radical cations, determined by LFP experiments, decrease by increasing the electron-donating power of the arylsulfinyl Y substituent and to a smaller extent by increasing the electron-withdrawing power of the benzylic X substituent. A solvent nucleophilic assistance to the C-S bond cleavage has been suggested, supported by the comparison of substituent effects on the same process occurring in aryl tert-butyl sulfoxide radical cations. DFT calculations, performed to determine the bond dissociation free energy in the radical cations, the transition state energies associated with the unimolecular C-S bond cleavage, and the charge and spin delocalized on their structures, were also useful to endorse the nucleophilic assistance to the C-S scission.
- Del Giacco, Tiziana,Lanzalunga, Osvaldo,Lapi, Andrea,Mazzonna, Marco,Mencarelli, Paolo
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p. 2310 - 2318
(2015/09/08)
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- Co-C bond cleavage in the reactions of alkyl, benzyl and heteroaromaticmethyl cobaloximes with arene sulfenyl chloride: Homolytic and heterolytic pathways
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The reactions of arene sulfenyl chlorides, ArSCl, (Ar=Ph, C6Cl5, 2,4 (NO2)2C6H3) with organocobaloximes, RCo(dmgH)2Py, (R=alkyl, benzyl and heteroaromaticmethyl) were carried out under thermal and photochemical conditions. A variety of organic and organometallic products are formed depending upon the substrate cobaloxime. For 3-methoxybenzyl and heteroaromaticmethyl cobaloximes the results suggest that they represent a unique class of cobaloximes whereby both the aromatic ring as well as the Co-C bond are highly activated towards attack by the arene sulfenyl chloride. Both homolytic as well as heterolytic pathways are operative.
- Gupta,Dixit, Vandana,Das, Indira
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