Regioselective carbon–carbon bond formation of 5,5,5-trifluoro-1-phenylpent-3-en-1-yne

• Motoki Naka,
• Tomoko Kawasaki-Takasuka and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2013, 9, 2182–2188, doi:10.3762/bjoc.9.256

• electrophiles, under equilibration of the possible two anionic species. Keywords: additives; computation; Li···F chelation; deprotonation; electron-withdrawing effect; organo-fluorine; Introduction We have previously reported [1] the interesting behavior of (E)-1-chloro-3,3,3-trifluoropropene ((E)-1) [2][3][4

• initial Hb abstraction from (E)-1 and the resultant Int-1 was stabilized by the energetically favorable 5-membered intramolecular Li···F chelation [5]. This intermediate Int-1 experienced Fritsch–Buttenberg-Wiechell (FBW) rearrangement [6][7] to give 3,3,3-trifluoropropyne, and Int-2 derived from this

• ] of the trans-disposed chlorine atom. However, it is also likely that the anionic intermediate produced after Hb abstraction would prefer the reaction course to 2 by way of FBW rearrangement because of its lower stability than Int-1 with loss of the possibility for Li···F chelation. It was not only