Tin for organic synthesis. 10. Unconventional regiospecific syntheses of aromatic carbonamides and thiocarbonamides by means of tin-mediated Friedel-Crafts reactions
摘要:
Friedel-Crafts reactions of stannylarenes 1 with tosyl isocyanate (TsNCO, 2) give N-tosylcarbonamides 3 via ipso substitution of the stannyl group. Thus, unconventionally substituted aromatic carbonamides can be obtained. The combination of the reaction of 1 and 2 with that of 1 and chlorosulfonyl isocyanate (14) allows one-pot syntheses of N-(arylsulfonyl)-substituted aromatic carbonamides with optional substitution patterns on both aromatic rings. The known ipso-specific substitutions of stannylarenes with 14 are extended to bi- and tricyclic arenes as well as to thiophenes 6 and 22. One stannyl group can serve as a leaving group for two aromatic systems, as shown with diaryldialkyltins 29. Also, stannylalkanes such as 27 react with 14 to afford alkylsulfonyl isocyanates and products of further reactions, such as 28. From the reactions of 1 with ethoxycarbonyl isothiocyanate (32), ortho- and meta-substituted aromatic thiocarbonamides 33 which are potential precursors for further syntheses, are accessible. The scope, limitations, and mechanism of these electrophilic substitutions are outlined.
Copper-mediated sulfonylation of aryl iodides and bromides with arylsulfonyl hydrazides in PEG-400
作者:Xiangmei Wu、Yan Wang
DOI:10.1039/c8nj00075a
日期:——
Sulfonylation using stable and readily available arylsulfonyl hydrazides and aryliodides or bromides mediated by cupric acetate has been achieved. Using polyethyleneglycol (PEG-400) as an eco-friendly medium, the couplingreaction could afford a series of unsymmetrical diaryl sulfones in moderate to good yields without the presence of additional ligands and base.
A new and efficient approach adopting copper-catalyzed cross-coupling of sulfonyl hydrazides with aryltriazenes has been developed to synthesize aryl sulfones using Brønsted acidic ionic liquid as promoter under ambient conditions. The process employs stable and easy to handle reacting partners, and is endowed with broad substrate scope.
Visible-light-driven electron donor–acceptor complex induced sulfonylation of diazonium salts with sulfinates
作者:Xin Liang、Yufei Li、Qing Xia、Lan Cheng、Jianbo Guo、Pei Zhang、Weihua Zhang、Qingmin Wang
DOI:10.1039/d1gc03239a
日期:——
work reports an efficient sulfonylation reaction enabled by a visible-light-induced radical coupling reaction between phenyl/heterocyclic diazoniumsalts and sulfinates. Mechanistic experiments disclosed the formation of a versatile electron donor–acceptor (EDA) complex. This transformation is characterized by an easy operational procedure under mild conditions which avoids transition metals, ligands,
A Simple Metal Free Oxidation of Sulfide Compounds
作者:Ravindra B. Wagh、Jayashree M. Nagarkar
DOI:10.1007/s10562-016-1932-1
日期:2017.1
AbstractThis work reports simple, efficient, selective protocol for the oxidation of sulfide compounds. Various sulfides were selectively and completely converted into their corresponding sulfoxides and sulfones using H2O2 as an oxidant in presence of catalytic amount of caprylic acid. The reaction proceeds at room temperature to give sulfoxide and by increasing the reaction temperature to 50 °C, this