A Pd(0)-Catalyzed Direct Dehydrative Coupling of Terminal Alkynes with Allylic Alcohols To Access 1,4-Enynes
摘要:
A direct dehydrative coupling of terminal alkynes with allylic alcohols catalyzed by Pd(PPh3)(4) with an N,P-ligand assisted by Ti(OiPr)(4) has been developed. The coupling reaction tolerates various functional groups, providing a valuable synthetic tool to access 1,4-enynes.
the directly dehydrative cross-coupling of allylicalcohols with terminal alkynes was developed. This calcium salt cocatalyst facilitates the oxidative addition of the palladium catalyst (1 mol %) to the C-OH bond. Then, the in situ-generated hydroxide ion deprotonates the terminal alkynes to promote the formation of the allylalkynylpalladium intermediate, liberating water as the only byproduct. This
Palladium-Catalyzed Hydroalkynylation of Alkylidenecyclopropanes
作者:Lara Villarino、Fernando López、Luis Castedo、José L. Mascareñas
DOI:10.1002/chem.200901821
日期:2009.12.14
promote the addition of CH bonds of terminal alkynes (2) to alkylidenecyclopropanes (1). The reaction gives rise to 1,4‐enynes (3) in good yields. The catalytic cycle probably consists of a Pd‐catalyzed CH activation of the terminal alkyne, a regioselective hydropalladation followed by distal bond cleavage of the alkylidenecyclopropane, and a final reductive elimination.