- Phosphine-Catalyzed Vinylation at Low Acetylene Pressure
-
The vinylation of various nucleophiles with acetylene at a maximum pressure of 1.5 bar is achieved by organocatalysis with easily accessible phosphines like tri-n-butylphosphine. A detailed mechanistic investigation by quantum-chemical and experimental methods supports a nucleophilic activation of acetylene by the phosphine catalyst. At 140 °C and typically 5 mol % catalyst loading, cyclic amides, oxazolidinones, ureas, unsaturated cyclic amines, and alcohols were successfully vinylated. Furthermore, the in situ generation of a vinyl phosphonium species can also be utilized in Wittig-type functionalization of aldehydes.
- Bienewald, Frank,Comba, Peter,Hashmi, A. Stephen K.,Menche, Maximilian,Rominger, Frank,Schafer, Ansgar,Schaub, Thomas,Sitte, Nikolai A.,Tuzina, Pavel
-
p. 13041 - 13055
(2021/09/18)
-
- Preparation method of lansoprazole key intermediate
-
The invention relates to a preparation method of a lansoprazole key intermediate. According to the technical scheme, the preparation method comprises the following steps: firstly, respectively preparing (2, 2, 2-trifluoroethoxy)ethylene (a compound 7) and 3-amino-4-chloro-2-methylbut-2-enoic acid ethyl ester (a compound 9); and then reacting the compound 7 with the compound 9 to prepare 6-(chloromethyl)-5-methyl-4-(2, 2, 2-trifluoroethoxy)-2,3,4,5- tetrahydropyridine; finally, oxidizing 6-(chloromethyl)-5-methyl-4-(2, 2, 2-trifluoroethoxy)-2, 3, 4, 5-tetrahydropyridine (compound 10) by hydrogen peroxide under the catalytic action of Mn(O)-Salon to generate 2-(chloromethyl)-3-methyl-4-(2, 2, 2-trifluoroethoxy)pyridine (compound 5). According to the technical scheme, danger is reduced, energy consumption is reduced, and the method is more suitable for large-scale industrial production.
- -
-
Paragraph 0033; 0037; 0041; 0045; 0049; 0053; 0057; 0061
(2020/07/13)
-