136908-27-5Relevant academic research and scientific papers
Reaction Route and Mechanism of the Direct N-Alkylation of Sulfonamides on Acidic Mesoporous Zeolite β-Catalyst
Fu, Wenqian,Shen, Runsheng,Bai, Enhui,Zhang, Lei,Chen, Qun,Fang, Zhongxue,Li, Guangchao,Yi, Xianfeng,Zheng, Anmin,Tang, Tiandi
, p. 9043 - 9055 (2018/09/11)
Development of highly active heterogeneous catalysts with strong acidity and mesoporous structure is a highly attractive strategy for organic synthesis. In this study, a mesoporous zeolite beta (HBeta-M) with bulky particle size and strong acidity was synthesized and used in the direct N-alkylation of sulfonamides with alcohols. The strongly acidic HBeta-M had a higher intrinsic activity with initial turnover frequency of 11 × 10-2 s-1 than those of H-form mordenite nanosheets (3.3 × 10-2 s-1) and montmorillonite (4.0 × 10-2 s-1) catalysts. The experiment and characterization results demonstrate that there are two parallel reaction routes on the acidic catalysts. One route is the reaction of benzhydrol with p-toluenesulfonamide (route I). Another route is the reaction of dibenzhydryl ether, arising from route I, with p-toluenesulfonamide (route II), which is found in this work. The reaction rate of route I (13 × 10-3 mol kg-1 s-1) was higher than that of route II (9.8 × 10-3 mol kg-1 s-1) on HBeta-M, but route II predominantly contributed to the formation of the target product with high selectivity. Hereby, a complete reaction mechanism is proposed in this work.
Secondary Benzylation Using Benzyl Alcohols Catalyzed by Lanthanoid, Scandium, and Hafnium Triflate
Noji, Masahiro,Ohno, Tomoko,Fuji, Koji,Futaba, Noriko,Tajima, Hiroyuki,Ishii, Keitaro
, p. 9340 - 9347 (2007/10/03)
The combination of a secondary benzyl alcohol and a metal triflate (e.g., La, Yb, Sc, and Hf triflate) in nitromethane was a highly effective secondary-benzylation system. Secondary benzylation of carbon (aromatic compounds, olefins, an enol acetate), nitrogen (amide derivatives), and oxygen (alcohols) nucleophiles was carried out with a secondary benzyl alcohol and 0.01-1 mol % of a metal triflate in the presence of water. Secondary benzyl alcohols and nucleophiles bearing acid-sensitive functional groups (e.g., tert-butyldimethylsilyloxy and acetoxy groups and methyl and benzyl esters) could be used for alkylation. Hf(OTf)4 was the most active catalyst for this alkylation, and trifluoromethanesulfonic acid (triflic acid, TfOH) was also a good catalyst. The catalytic activity of metal triflates and TfOH increased in the order La(OTf)3 3 3 4. A mechanistic study was also performed. The reaction of 1-phenylethanol (4a) in the presence of Sc(OTf) 3 in nitromethane gave an equilibrium mixture of 4a and bis(1-phenylethyl) ether (54). Addition of a carbon nucleophile to the equilibrium mixture gave alkylated product in high yield.
A simple and effective method for phosphoryl transfer using TiCl4 catalysis
Jones, Simon,Selitsianos, Dimitrios
, p. 3671 - 3673 (2007/10/03)
(graph presented) A number of Lewis acids have been evaluated as catalysts for the phosphoryl transfer, the most efficient being TiCl4. Application of this methodology to the phosphorylation of a number of representative target alcohols is presented.
