Methylprenyl and Prenyl Protection for Sulfonamides
摘要:
2-Methylprenyl (MePre) is an efficient protection for sulfonamides. The acidic cleavage of this group leads to volatile by-products and the product can be obtained in high purity without additional purification. MePre group is resistant to Pd/C-catalysed hydrogenolysis at 1 atm, Suzuki-Miyaura reaction, Ni(0) catalysis conditions and oxidising reagents such as NIS and DDQ. The prenyl (Pre) group can also be used to protect sulfonamides in certain cases; however, the substrate scope is limited due to the side product formation.
Gold-Catalyzed <i>syn</i>-1,2-Difunctionalization of Ynamides via Nitrile Activation
作者:Rajeshwer Vanjari、Shubham Dutta、Manash P. Gogoi、Vincent Gandon、Akhila K. Sahoo
DOI:10.1021/acs.orglett.8b03830
日期:2018.12.21
Developed is an unprecedented Au(I)-catalyzed syn-1,2-difunctionalization of ynamides with 2-aminobenzonitriles via nitrile activation. The coupling between ynamides and 2-aminobenzonitriles is explicitly regioselective, providing a straightforward access to 2,4-diamino-substituted quinolines. Density functional theory (DFT) study provides insightful information and rationalizes the reaction pathway
Metal-free C–H sulfonamidation of pyrroles by visible light photoredox catalysis
作者:Andreas Uwe Meyer、Anna Lucia Berger、Burkhard König
DOI:10.1039/c6cc06111g
日期:——
We report a one-step procedure for the preparation of N-(2-pyrrole)-sulfonamides from sulfonamides and pyrroles. The reaction uses visiblelight, an acridinium dye as photocatalyst and oxygen as the terminal oxidant...
Preparation of Sulfonamides from Sodium Sulfonates: Ph3P ⋅ Br2 and Ph3P ⋅ Cl2 as a Mild Halogenating Reagent for Sulfonyl Bromides and Sulfonyl Chlorides
Arene- and alkanesulfonamides were prepared by treatment of the corresponding sodium sulfonates with triphenylphosphine dibromide or dichloride followed by amines in the presence of triethylamine via sulfonyl halides. Reactions of sodium aminosulfonates gave cyclized products. Amidation of p-toluenesulfonic acid with triphenylphosphine dichloride was also examined to give N-benzyl-p-toluenesulfonamide. Methyl p-toluenesulfonate was obtained by esterification of sodium p-toluenesulfonate via p-toluenesulfonyl chloride.
Diverse Reactions of Sulfonyl Chlorides and Cyclic Imines
作者:Jing Liu、Shili Hou、Jiaxi Xu
DOI:10.1080/10426507.2011.608097
日期:2011.12.1
6-dihydro-4H-oxazines and thiazines, 4,5-dihydro-3H-benzo[c]azepine, and 3,4-dihydroisoquinoline, to produce diverse products instead of β-sultam derivatives. The results indicate that alkanesulfonyl chlorides react with cyclic imines to generate N-alkanesulfonyl cyclic iminium ions, which are attacked by nucleophiles, such as water and chloride anion, in the reaction systems, affording addition products
Keteniminium‐Driven Umpolung Difunctionalization of Ynamides
作者:Shubham Dutta、Shengwen Yang、Rajeshwer Vanjari、Rajendra K. Mallick、Vincent Gandon、Akhila K. Sahoo
DOI:10.1002/anie.201915522
日期:2020.6.26
synthesis of novel triaryl‐substituted enamides is described. This transformation represents the first example of an umpolung regioselective unsymmetrical syn ‐1,2‐diarylation/aryl‐olefination of ynamides. The aryl moieties of the diazonium salt (electrophile) and boronic acid (nucleophile) are explicitly incorporated in the electrophilic α‐ and nucleophilic β‐position, respectively, of the ynamide