An investigation of the photochemistry of several a-acetylenic ketones was instituted. The photochemical behavior of 2-octyne-4-one 22 was compared with that of 2-octene-4-one 2j. Whereas the latter underwent only cis-trans olefin isomerization, the former proceeded efficiently to y-hydrogen abstraction products. Both photochemical and spectroscopic properties of 22. reveal its similarity to valerophenone 58. 4,4-dimethyl-1hexyne-3-one 23 was synthesized in order to study a-methyl effects in the photochemistry of ynones. 4,4-dimethyllhexyne-5-ene-3-one 24^ was also synthesized and a preliminary inspection of the photochemistry of 23. and 24 was made.