266325-19-3

Upstream product

• 37559-18-5 3-phenylprop-2-ynyl acetate 
• 1504-58-1 3-Phenyl-2-propyn-1-ol 
• 420121-38-6 methyl (3-phenylprop-2-yn-1-yl) carbonate 
• 673-32-5 1-Phenylprop-1-yne 
• 591-50-4 iodobenzene 
• 31930-36-6 ethyl (Z)-3-iodopropenoate 
• 31930-34-4 ethyl (Z)-3-bromopropenoate 
• 1794-48-5 1-bromo-3-phenylprop-2-yne 

Relevant academic research and scientific papers

Tuning of regioselectivity in the coupling reaction involving allenic/propargylic palladium species

Two different types of coupling patterns for the Pd(O)-catalyzed coupling reaction of allenic/propargylic zinc reagents with organic halides or propargylic carbonates (acetate) with the corresponding organometallic reagents were observed. After studying the controlling factors on the regioselectivity of this reaction, we demonstrated that the steric hindrance of both reactants and the types of organic halides determine the regioselectivity of this coupling reaction. By subtle choosing of the substrates, the regioselectivity can be tuned. On the basis of these results, new methodologies for the highly regio- and stereoselective synthesis of 6-substituted hex-5-yn-2-enoates and 4,6-dialkylhexa-2,4,5-trienoates have been developed. Some of the products synthesized by the carbonate protocol cannot be prepared by the lithiation protocol because the regioselectivity of lithiation of dialkyl-substituted internal alkynes is an intrinsic problem.

Unusual regioselectivity of Pd(0)-catalyzed coupling reaction of electron-deficient alkenyl halides with allenic/propargylic zinc reagents. Highly selective synthesis of 6-phenylhex-5-yn-2(or 3)-enoates/enitrile and 4-phenyl-6-substituted-hexa-2,4,5-trienoates

The Pd(0)-catalyzed coupling reaction of electron-deficient alkenyl halides with the organozinc formed by the subsequent treatment of 1- phenylalk-1-yne with n-BuLi and ZnBr2 with or without a catalytic amount of HgCl2 was studied. Both the allene-formation- and the alkyne-formation-type coupling reactions were observed with high regio- and stereoselectivity: the reaction of 1-phenylprop-1-yne afforded 6-phenylhex-5-yn-2(or 3)-enoates and -enitriles, while the reaction of 1-phenylhex-1-yne formed 4-phenyl-6- substituted-hexa-2,4,5-trienoates. A plausible explanation for the regioselectivity was discussed. The double bonds in 6-phenylhex-5-yn-2- enoates were prone to migrate to the position conjugated with the carbon- carbon triple bonds to form 6-phenylhex-5-yn-3-enoates at higher temperature. The migration did not occur in absence of an excess amount of allenic/propargylic zinc reagent or at low temperature.