Cooperative Catalysis: Enantioselective Propargylic Alkylation of Propargylic Alcohols with Enecarbamates Using Ruthenium/Phosphoramide Hybrid Catalysts
The diastereo‐ and enantioselectivepropargylicalkylation of propargylicalcohols with E‐enecarbamates in the presence of a catalytic amount of thiolate‐bridged diruthenium complexes bearing an optically active phosphoramide moiety gives the corresponding propargylic alkylated products (up to 97 % ee).
1,1-Diaryl-1-penten-4-yn-3-ols react with diphenylphosphine oxide in the presence of a thiolate-bridgeddirutheniumcomplex as a catalyst and give high yields of aryl(diphenyl)phosphine oxide products via an initial substitution followed by a cyclization at the produced allene intermediate. [reaction: see text]
Ruthenium-catalyzed enantioselective propargylation of l-(triisopropylsilyl)-1H-indoles with propargylicalcohols gives the corresponding β-propargylated indoles in good yields with high enantioselectivity. Reactions with l-(l-naphthyl)prop-2-yn-l-ol achieve the highest enantioselectivity (up to 95% ee).
Ruthenium-catalyzed enantioselective propargylation of indoles with propargylic alcohols affords the corresponding beta-propargylated indoles in good yields with a high enantioselectivity (up to 95% ee). A remarkable effect of the nature of the N-substituent of indoles is observed for the enantioselectivity of the propargylated indoles. The preparative method described in this paper may provide a novel protocol for asymmetric Friedel-Crafts alkylation of indoles using propargylic alcohols as a new type of electrophiles.