作者:Alan R. Katritzky、Qiu-He Long、Ping Lue、Andrzej Jozwiak
DOI:10.1016/s0040-4020(01)81471-x
日期:——
A new, facile preparation of enamines was achieved via a two-step sequence: (i) the ready formation of an N-(α-aminoalkyl)benzotriazole derivative from equimolar amounts of benzotriazole, an aldehyde, and a secondary amine, (ii) the elimination of benzotriazole from the derivative by sodium hydride in tetrahydrofuran (THF). The method provides enamines in good overall yields based on the quantity of
Enamines derived from ketones or aldehydes react smoothly with trialkyl orthoformates in the presence of Lewis acids to give β-ketoacetals in good yields.
Verbindungen der Formel
worin R¹ Alkyl oder trans-4-Alkylcyclohexyl und R² Alkyl, Alkoxy oder trans-4-Alkylcyclohexyl bedeuten,
deren Herstellung, flüssigkristalline Gemische und die Verwendung für elektro-optische Zwecke.
AbstractThe hydroamination of terminal alkynes (RCCH=phenylacetylene, 4‐methylphenylacetylene, 4‐fluorophenylacetylene, 1‐hexyne, methyl 2‐propynyl ether, prop‐2‐yn‐1‐ol) with secondary amines (piperidine, pyrrolidine, morpholine, piperazine, methylpiperazine, 4‐methylpiperidine and 3‐methylpiperidine) was achieved in high yield (up to 99%), regioselectivity (only anti‐Markovnikov product) and stereoselectivity (only E‐isomers) within a maximum of 5 h in reactions catalyzed by the tungsten tetracarbonyl complex cis‐[W(CO)4(piperidine)2] at 90 °C without any additional solvent.magnified image