Nitration of phenylpropiolic acid derivatives in HSO3F and reactions of vinyl type cations formed therefrom

Abstract

Nitration of phenylpropiolic acid derivatives ArCºCX (X=CN, CO 2 Me) in HSO 3 F at -75...50°C afforded mononitro compounds, for instance, m-O 2 NC 6 H 4 CºCX. Vinyl type cations generated in HSO 3 F from methyl 3-arylpropiolates ArC + =CHCO 2 Me react along two pathways. The first among them results in formation of fluorosulfonates ArC(OSO 2 F)=CHCO 2 Me, and the second one after the attack of vinyl cation on the aryl moiety of the substrate affords a dimer that on nitration is converted into a nitro product with conserved triple bond.

Protonation of 3-Arylpropynoic Acid Derivatives in Superacids

“…We recently initiated studies on protonation and subsequent transformations of acetylenic compounds in superacidic media [1][2][3][4][5][6], which opened new prospects in the application of superacids [7] in synthetic organic chemistry. Stang [8,9] and Olah [10] were the first to report on the addition of superacids (HSO 3 F and CF 3 SO 3 H) to alkyl-and dialkylacetylenes with formation of the corresponding vinyl fluorosulfonates and trifluoromethanesulfonates.…”

Reactions of Vinyl Type Carbocations Generated in Fluorosulfonic Acid with Benzene Derivatives. New Synthesis of Alkyl 3,3-Diarylpropenoates

“…The synthesis and properties of acetylene derivatives, methyl 3-(4-methoxyphenyl)propynoate (I), methyl 3-(4-methylphenyl)propynoate (II), methyl 3-phenylpropynoate (III), methyl 3-(4-fluorophenyl)propynoate (IV), ethyl 3-(4-iodophenyl)propynoate (Va), ethyl 3-(4-methoxy-3-nitrophenyl)propynoate (Vb), 3-phenylpropynoic acid (VI), and 3-phenylpropynenitrile (VIIa), were reported in [8,9]. 4-(4-Chlorophenylethynyl)benzonitrile (VIIb) and methyl 4-phenylethynylbenzoate (VIIc) were described in [13]; and diethyl phenylethynylphosphonate (VIII) was synthesized according to [14].…”

“…While studying transformations of acetylenic compounds in superacids [4][5][6][7][8][9][10] we have revealed a key reaction based on protonation of the triple bond in acetylene derivative to give vinyl type carbocation which then reacts with appropriate aromatic substrate [6][7][8]. It seems to be reasonable to estimate the synthetic potential of this new reaction and its scope upon variation of donor-acceptor properties of substituents in the acetylenic and aromatic components.…”