A ruthenium-catalyzed propargylic alkylation of propargylic alcohols with various ketones provides the corresponding γ-keto acetylene products in high yields under mild and neutral reaction conditions with complete regioselectivities.
Y. Nishibayashi, I. Wakiji, Y. Ishii, S. Uemura, M. Hidai, J. Am. Chem. Soc., 2001, 123, 3393-3394.
Ketones readily undergo conversion to enol silanes in the presence of a trialkylamine base and trimethylsilyl trifluoromethanesulfonate and add to propargyl cations, which are generated in situ through a TMSOTf-promoted ionization of propargyl carboxylates. A range of enol silane precursors and propargyl carboxylates reacts efficiently to provide β-alkynyl ketones in good yields.
C. Wade Downey, D. N. Confair, Y. Liu, E. D. Heafner, J. Org. Chem., 2018, 83, 12931-12938.