134206-08-9Relevant academic research and scientific papers
Reactions of alkyl 4-hydroxybut-2-ynoates with arenes under superelectrophilic activation with triflic acid or HUSY zeolite: Alternative propargylation or allenylation of arenes, and synthesis of furan-2-ones
Devleshova, Natalia A.,Lozovskiy, Stanislav V.,Vasilyev, Aleksander V.
, (2019/08/27)
Reactions of alkyl 4-aryl(or 4,4-diaryl)-4-hydroxybut-2-ynoates [Ar(H or Ar')(OH)C4–C3≡C2–CO2Alk] with arenes under the action of triflic acid TfOH or HUSY zeolite result in the formation of two main compounds, aryl substituted furan-2-ones or products of propargylation of electron rich arenes. Key reactive intermediates in these transformations are the corresponding O,O-diprotonated forms of starting butynoates, Ar(H or Ar')(+OH2)C4–C3≡C2– C(=O+H)(OAlk), dehydration of which gives rise to mesomeric propargyl-allenyl cations Ar(H or Ar')(OH)4C+–C3≡C2–C(=O+H)(OAlk) ? Ar(H or Ar')(OH)4C = C3 = 2C+–C(=O+H)(OAlk), having two electrophilic centers on the carbons C4 and C2 respectively. Reactions of these species with arenes at C4 lead to products of arene propargylation, alternatively, reactions at C2 result in allenylation of arenes, followed by further transformation into furan-2-ones. Using quantum chemical calculations by the DFT method, it has been shown that the reactivity of such propargyl-allenyl cations is mainly explained by orbital factors. Plausible reaction mechanism is discussed.
Synthesis of trisubstituted allenamides utilizing 1,2-rearrangement of dialkoxyphosphoryl moiety under Br?nsted base catalysis
Kondoh, Azusa,Ozawa, Ryosuke,Terada, Masahiro
supporting information, p. 1164 - 1167 (2019/09/07)
A new method for the synthesis of trisubstituted allenamides was developed by utilizing the 1,2-rearrangement of a dialkoxyphosphoryl moiety from carbon to nitrogen under Br?nsted base catalysis. The reaction would involve the catalytic generation of an α-amino propargyl anion through the key rearrangement, the addition to an electrophile at the α-position of the anionic intermediate, and the unprecedented rearrangement of a phosphoramidate moiety of the adduct, providing trisubstituted allenamides that are difficult to synthesize by using conventional methods.
: NBu4NPF6 promoted regioselective cascade synthesis of functionally embellished naphthofurans under acid, metal & solvent free conditions
Pareek, Abhishek,Dada, Ravikrishna,Rana, Monika,Sharma, Anuj K.,Yaragorla, Srinivasarao
, p. 89732 - 89743 (2016/10/03)
nBu4NPF6 mediated highly regioselective synthesis of functionally embellished naphthofurans has been achieved from easily available naphthols and propargyl alcohols through a cascade benzylation, oxacyclisation (5-exo dig) and isomerization under solvent free conditions. The reaction works in a short time through dibenzyl ether formation followed by the decomposition to the carbocation to furnish the high yielding products with large substrate scope. The synthetic utility of the products is demonstrated through C(sp3)-H functionalization. In addition, we investigated selected naphthofurans for their anti-amyloidogenic properties. Preliminary studies suggest that these are excellent inhibitors for amyloid formation, a hallmark for several neurodegenerative diseases.
