Synthesis of Arylallenes by Palladium-Catalyzed Retro-Propargylation of Homopropargyl Alcohols
摘要:
Treatment of tertiary homopropargyl alcohol with aryl halide under palladium catalysis provided arylallenes regioselectively. The reaction includes retropropargylation, which proceeds in a concerted fashion via a cyclic transition state and transfers the stereochemistry of homopropargyl alcohols through C-C bond cleavage. The present method enables the use of homopropargyl alcohols as allenylmetal equivalents.
Cesium Hydroxide: A Superior Base for the Catalytic Alkynylation of Aldehydes and Ketones and Catalytic Alkenylation of Nitriles
摘要:
The efficient addition of terminal alkynes to aldehydes or ketones to give propargyl alcohols in yields of 66-96 % can be achieved by activation with catalytic amounts of CsOH⋅H2 O [Eq. (a)]. A CsOH-catalyzed addition of acetonitrile derivatives to terminal alkynes is also possible.