69699-21-4Relevant academic research and scientific papers
Microwave-assisted catalytic intermolecular hydroamination of alkynes
Bytschkov, Igor,Doye, Sven
, p. 4411 - 4418 (2001)
Irradiation of reaction mixtures containing an alkyne, an amine, and a catalytic amount of Cp2TiMe2 in toluene with microwaves at a frequency of 2.45 GHz and a power output of 180-300 W results in fast reactions to give the corresponding hydroamination products. The initially formed imines can easily be reduced to secondary amines by use of H2/Pd, LiAlH4, or NaCNBH3/p-TsOH. The microwave-assisted hydroamination reactions go to completion within one tenth (or less) of the time required for reactions run conventionally in an oil bath at 105 °C. By using the microwave technology, it is possible to achieve turnover frequencies TOF > 10 h-1. Furthermore, when Cp2TiMe2 is used as the catalyst, hydroamination products of terminal alkynes can be isolated in reasonable yields for the first time. The addition of amines to terminal alkynes gives access to both the Markovnikov and the anti-Markovnikov products. Observed regioselectivities are different for terminal aryl- and alkylalkynes.
