A transition-metal- and catalyst-free hydrogenation of a wide range of aryl halides is promoted by bases using either aldehydes or alcohols as hydrogen source. One equivalent of benzaldehyde affords an equal yield as that of 0.5 equiv of benzyl alcohol. The kinetic study reveals that the initial rate of PhCHO is nearly 4 times faster than that of BnOH. Radical trapping experiments indicate the radical nature of this reaction.
H.-X. Zheng, X.-H. Shan, J.-P. Qu, Y.-B. Kang, Org. Lett., 2017, 19, 5114-5117.
A simple ruthenium catalyst achives a semihydrogenation of diaryl alkynes to the corresponding E-alkenes in very good yields using alcohols as the hydrogen source. Best results were obtained using benzyl alcohol as the hydrogen donor, although biorenewable alcohols such as furfuryl alcohol could also be applied.
A. Ekebergh, R. Begon, N. Kann, J. Org. Chem., 2020, 85, 2966-2975.