In combination with TFA, "ionic hydrogenation" of alkenes occurs. This can be a useful alternative to catalytic hydrogenation, since selective reduction, e.g. of the more branched double bond of a diene can be achieved. For a review of ionic hydrogenation, see: Synthesis, 633 (1974)For trans-hydrosilylation of alkynes, catalyzed by AlCl3, see: J. Org. Chem., 61, 7354 (1996); 64, 2494 (1999). ɑ?-Enones are reduced selectively to saturated ketones In the presence of TFA: Synthesis, 420 (1973); or Wilkinson’s catalyst (Chlorotris(triphenyl-phosphine)-rhodium(I)-, 10468): Tetrahedron Lett., 5035 (1972); Organometallics, 1, 1390 (1982). With TFA, aliphatic ketones are reduced to secondary alcohols, whereas aromatic ketones and aldehydes are further reduced to the hydrocarbons: J. Org. Chem., 38, 2675 (1973).
