Asymmetric Propargylic Alkylation with Acetone

As described in the previous section, the ruthenium-catalyzed propargylic alkylation of propargylic alcohols with acetone afforded the corresponding alkylated products in high yields with complete selectivity [27]. When an optically active 1 -phenyl-2 -propyn-1 -ol was treated with acetone at room temperature in the presence of la as catalyst, only a racemic alkylated product was obtained [27]. This result 

The best enantioselectivity (35% ee) was observed in the reaction of l-(l-naphthyl)-2-propyn-l-ol with acetone in the presence of a complex bearing a 1-naphthylethylthio-lato moiety as a chiral ligand. Although the enantioselectivity is not yet satisfactory, this was the first example of an enantioselective propargylic substitution reaction catalyzed by transition metal complexes [27]. It is noteworthy that the chiral thiolate-bridged ligands work to control the chiral environment around the diruthenium site. 

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