Deprotonation of ternary iminium salts

Deyrup, James A.; Szabo, William A.

doi:10.1021/jo00902a008

Cited by 25 publications

(9 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, the geminal and vicinal substituent separations are large because of the compressed internal angles of a small r i n g .~n equivalent rationalibegins with the assumption that the ylides cannot adopt the all-planar structure that is the ground state of less congested ylides (25) and that they are already substantially twisted in their most stable conformations. Whichever view is taken, the very fast ring closures of the ylides encountered here are attributed to a raised ground state energy level, as proposed by others (26,27).…”

supporting

confidence: 71%

Enaminic reactions of 4-tert-butyl-3,3-dimethyl-5-methylene-Δ¹-1,2,4-triazoline. Novel heterocycles by sequential [2 + 2] cycloaddition and ylide-forming [3 + 2] cycloreversion

Schwan¹,

Warkentin²

1988

Can. J. Chem.

View full text Add to dashboard Cite

Triazoline 1, which is formally an α azoenamine, reacts with dimethyl acetylenedicarboxylate, acrylonitrile, methacrylonitrile, methyl methacrylate, phenylisocyanate, and sulfene to form products that appear to be derived from a common first step, the formation of a dipolar intermediate (e.g., 5). That intermediate may close to form either a 4-membered ring (6, 8) or ring-open to 7 with subsequent closure to a 5-membered ring (4). Alternatively it may lead to an enamine with extended conjugation (10, 11) by a sequence of proton transfers. The spirotriazolines (e.g., 6) are unstable and decompose by loss of N2 to form spiro aziridines (e.g., 3). Hydrogen cyanide, from acetone cyanohydrin, converts 1 to the cyanoaziridine 13 while methanol adds reversibly under acidic conditions to form 17.

show abstract

supporting

confidence: 71%

Enaminic reactions of 4-tert-butyl-3,3-dimethyl-5-methylene-Δ¹-1,2,4-triazoline. Novel heterocycles by sequential [2 + 2] cycloaddition and ylide-forming [3 + 2] cycloreversion

Schwan¹,

Warkentin²

1988

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…In 1975, Deyrup and Szabo proposed an alternative synthetic procedure to obtain substituted aziridines from the ring closure of azomethine ylides by deprotonation of iminium salts. [25] Iminium salts were generated by alkylation of imines with the highly reactive methyl fluorosulfonate. After the successful formation of azomethine ylides via deprotonation of iminium salts, they extended this study to keteniminium salts.…”

Section: Formation Of Kis From Keteniminesmentioning

confidence: 99%

“…Ynamides still have a strong polarization This study aims to give essential insights into the mechanistic aspects of KI formation and the role of the substituents infacilitate the design of KI intermediates, which will ultimately allow access to complex compounds. In this regard, the aforementioned four different methods for the formation of keteniminium salts, namely KI formation from α-haloenamines with Lewis acids, [28,29] and triflation of amides, [15] alkylation of ketenimines, [16,25] and protonation of ynamines and ynamides [17,19,27] were thoroughly examined using a density functional theory (DFT) approach. Furthermore, a broad range of substituents was examined and their potential contributions to the formation of KIs were elucidated.…”

Section: Formation Of Kis From Ynamines and Ynamidesmentioning

confidence: 99%

Formation of Keteniminium Salts: Mechanistic Aspects and Substituent Effects

Aktaş

Tanriver

Quinodoz

et al. 2022

Preprint

View full text Add to dashboard Cite

Keteniminium salts (KIs) are versatile intermediates in synthetic organic chemistry. Elucidation of the mechanistic aspects of KI formation reactions facilitates the design of KI intermediates that give access to complex compounds. In this study, in order to provide a comprehensive understanding of KI formation, various mechanisms were investigated using a density functional theory approach. Particularly, Ghosez’s KI formation mechanism, by activation of an amide with triflic anhydride, was extensively elaborated, since this procedure occurs under mild conditions and is, by far, the most frequently used method. Moreover, a broad range of substituents was examined to give insight on their potential contributions to the ease of formation of KIs. The effect of substituents on the reactivity of the corresponding starting amides was inspected by means of energetics, population analysis, frontier molecular orbitals (FMO) and reactivity descriptors. Computed data shows that electron donating groups lower the activation barrier by increasing the electron density of the amide carbonyl oxygen. Additionally, distortion/interaction model also confirmed the energetic outcomes. In addition, investigation of KI reactivity using FMO, and reactivity descriptors displayed that KI reactivity is inversely correlated with amide reactivity. Lastly, experimental outcomes are in line with computational predictions. We suggest that the reactivity of the amide has a crucial impact on the ease of KI formation and the reactivity of the corresponding KIs. This study gives pivotal insights into mechanistic aspects of KI formation and the role of the substituents.

show abstract

“…The iminium salt Ph 2 C=N + Me 2 ·FSO 3 – could be deprotonated with very strong bases and provided an aziridine in low yield. 26 However, the electron-withdrawing CF 3 substituent may facilitate the iminium N + CH 3 deprotonation. 27 An indirect 1,3-proton transposition mediated by a water molecule, as described by Rosenau et al, 28 could be an alternative.…”

Section: Table 1 Reactions Of Iminium Salts 3a B With Alkoxybenzenmentioning

confidence: 99%

1,3-Bis(trifluoromethyl)prop-2-ene 1-Iminium Salts: Reactions with Alkoxybenzenes and Anilines

Keim¹,

Jasarevic²,

Miller³

et al. 2021

Synthesis

View full text Add to dashboard Cite

1,3-Bis(trifluoromethyl)prop-2-ene 1-iminium triflate salts were prepared for the first time and some synthetic applications as 1,3-biselectrophilic building blocks were established. They were found to react with dimethoxybenzenes or methylene-1,2-dioxybenzenes to furnish vinylogous trifluoroacetylaton products (4-aryl-1,1,1,5,5,5-hexafluoropent-3-en-2-ones) and 1-dialkylamino-1,3-bis(trifluoromethyl)-1H-indenes. With aniline and ring-substituted anilines, 2,4-bis(trifluoromethyl)quinolines were formed. An unusual 4H-pyran, formally a condensation product of the N,N-dimethyl-1,3-bis(trifluoromethyl)prop-2-en-1-iminium ion and its enaminone precursor, is also reported.

show abstract

Deprotonation of ternary iminium salts

Cited by 25 publications

References 9 publications

Enaminic reactions of 4-tert-butyl-3,3-dimethyl-5-methylene-Δ¹-1,2,4-triazoline. Novel heterocycles by sequential [2 + 2] cycloaddition and ylide-forming [3 + 2] cycloreversion

Enaminic reactions of 4-tert-butyl-3,3-dimethyl-5-methylene-Δ¹-1,2,4-triazoline. Novel heterocycles by sequential [2 + 2] cycloaddition and ylide-forming [3 + 2] cycloreversion

Formation of Keteniminium Salts: Mechanistic Aspects and Substituent Effects

1,3-Bis(trifluoromethyl)prop-2-ene 1-Iminium Salts: Reactions with Alkoxybenzenes and Anilines

Contact Info

Product

Resources

About

Deprotonation of ternary iminium salts

Cited by 25 publications

References 9 publications

Enaminic reactions of 4-tert-butyl-3,3-dimethyl-5-methylene-Δ1-1,2,4-triazoline. Novel heterocycles by sequential [2 + 2] cycloaddition and ylide-forming [3 + 2] cycloreversion

Enaminic reactions of 4-tert-butyl-3,3-dimethyl-5-methylene-Δ1-1,2,4-triazoline. Novel heterocycles by sequential [2 + 2] cycloaddition and ylide-forming [3 + 2] cycloreversion

Formation of Keteniminium Salts: Mechanistic Aspects and Substituent Effects

1,3-Bis(trifluoromethyl)prop-2-ene 1-Iminium Salts: Reactions with Alkoxybenzenes and Anilines

Contact Info

Product

Resources

About

Enaminic reactions of 4-tert-butyl-3,3-dimethyl-5-methylene-Δ¹-1,2,4-triazoline. Novel heterocycles by sequential [2 + 2] cycloaddition and ylide-forming [3 + 2] cycloreversion

Enaminic reactions of 4-tert-butyl-3,3-dimethyl-5-methylene-Δ¹-1,2,4-triazoline. Novel heterocycles by sequential [2 + 2] cycloaddition and ylide-forming [3 + 2] cycloreversion