Transformations of alkene and alkyne substrates relevant to p-Lewis acid catalysis have been performed using low-valent Ga(I) species for the first time. [Ga(I)(PhF) 2 ] + [Al(OR F ) 4 ] À and gallium dichloride (i. e. [Ga(I)] + [GaCl 4 ] À ) proved to be efficient catalysts for cycloisomerizations, Friedel-Crafts reactions, transfer hydrogenations, and reductive hydroarylations. Their activity is compared to more common Ga(III) complexes. This study shows that even the readily available and yet overlooked gallium dichloride salt can be a more active p-Lewis acid catalyst than gallium trichloride or other Ga(III) species.

[IPr·InBr2][SbF6] (2) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) has been synthesized and characterized in the solid state. This complex proved to be a very active catalyst for hydroarylations, transfer hydrogenations, and cycloisomerizations.