The Friedel-Crafts reaction is one of the most reliable and powerful CÀC bond forming tools in organic synthesis. [1] Recently, the development of an asymmetric Friedel-Crafts alkylation of aromatic compounds has received a great deal of attention. This reaction introduces chiral centers at the benzylic position of aromatic compounds, [2] and a variety of Lewis acids and organocatalysts are available to promote the reaction. [2,3] However, the successful examples of asymmetric Friedel-Crafts alkylation are still limited to reactions with three types of electrophiles such as epoxides, carbonyl compounds, activated alkenes, and their analogues. [2,3] We have recently disclosed the novel catalytic activity [4] of chalcogenolate-bridged diruthenium complexes [5] such as [{Cp*RuCl(m 2 -YR) }2 ] (Cp* = h 5 -C 5 Me 5 ; Y= S, Se, Te; R = Me, nPr, iPr) and [Cp*RuCl(m 2 -YR) 2 RuCp*(OH 2 )]OTf (Tf = trifluoromethanesulfonyl) for many organic transformations via ruthenium-allenylidene intermediates.[6] One of these transformations is the propargylation of aromatic compounds with propargylic alcohols. [7][8][9] We envisaged the development of a catalytic enantioselective propargylation of aromatic compounds as a new type of asymmetric FriedelCrafts alkylation of aromatic compounds by taking account of our previous development of the ruthenium-catalyzed enantioselective propargylic substitution reactions of propargylic alcohols with acetone (up to 82 % ee).[10] We report here a successful example of an asymmetric Friedel-Crafts alkylation by using propargylic alcohols as electrophiles.Treatment of 1-phenyl-2-propyn-1-ol (1 a) with 2-methylfuran (10 equiv) in ClCH 2 CH 2 Cl in the presence of a catalytic amount of a chiral thiolate-bridged diruthenium complex 2 a, (prepared in situ from the tetranuclear ruthenium(II) complex [Cp*RuCl] 4 and a chiral disulfide [10b] in THF at room temperature for 12 h), and NH 4 BF 4 at 60 8C for 3 h afforded 2-methyl-5-(1-phenyl-2-propynyl)furan (3 a), which was isolated in 75 % yield with 77 %