Coupling cyclizations with fragmentations for the preparation of heteroaromatics: quinolines from o-alkenyl arylisocyanides and boronic acids

Evoniuk, Christopher J.; Ly, Michelle; Alabugin, Igor V.

doi:10.1039/c5cc04391c

Cited by 55 publications

(29 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…of Mn III (acac) 3 . 212 A nitrogen-containing six-membered ring was likewise obtained by the cycloaromatization of eneallene-isonitrile 236 + , in turn easily obtained in situ from pyridinium 235 + , as the mesylate salt. In such a way, a quinoline biradical 237 + was generated that, upon intramolecular cyclization (via a formal [4+1] cycloaddition), afforded the end 11H-indolizino[1,2-b] quinolin-10-ium 238 + in a good yield (Scheme 63).…”

Section: Synthesis Of Heteroaromaticsmentioning

confidence: 99%

(Hetero)aromatics from dienynes, enediynes and enyne–allenes

et al. 2016

View full text Add to dashboard Cite

The construction of aromatic rings has become a key objective for organic chemists. While several strategies have been developed for the functionalization of pre-formed aromatic rings, the direct construction of an aromatic core starting from polyunsaturated systems is yet a less explored field. The potential of such reactions in the formation of aromatics increased at a regular pace in the last few years. Nowadays, there are reliable and well-established procedures to prepare polyenic derivatives, such as dienynes, enediynes, enyne-allenes and hetero-analogues. This has stimulated their use in the development of innovative cycloaromatizations. Different examples have recently emerged, suggesting large potential of this strategy in the preparation of (hetero)aromatics. Accordingly, this review highlights the recent advancements in this field and describes the different conditions exploited to trigger the process, including thermal and photochemical activation, as well as the use of transition metal catalysis and the addition of electrophiles/nucleophiles or radical species.

show abstract

Section: Synthesis Of Heteroaromaticsmentioning

confidence: 99%

(Hetero)aromatics from dienynes, enediynes and enyne–allenes

et al. 2016

View full text Add to dashboard Cite

show abstract

“…To our delight, in the presence of Mn(acac) 3 and phenyl boronic acid, substrate 1a underwent the selective 6- endo cyclization/fragmentation cascade. , Table outlines the screening process that leads to the optimized conditions (entry 3) which yielded exclusively the quinoline 2a in 86% yield. Slight excess (1.5 equiv) of boronic acid was needed, presumably to compensate for the side reactions, such as radical dimerization .…”

Section: Resultsmentioning

confidence: 99%

“…HRMS (ESI) m / z : [M+Na] + : Calcd for C 15 H 12 FNNaO 2 280.0742, Found: 280.0744. Spectral data match those previously reported …”

Section: Methodsmentioning

confidence: 99%

Coupling Radical Homoallylic Expansions with C–C Fragmentations for the Synthesis of Heteroaromatics: Quinolines from Reactions of o-Alkenylarylisonitriles with Aryl, Alkyl, and Perfluoroalkyl Radicals

Evoniuk

Gomes

et al. 2017

J. Org. Chem.

Self Cite

View full text Add to dashboard Cite

Selective addition of radicals to isonitriles can be harnessed for initiating reaction cascades designed to overcome the stereoelectronic restrictions on homoallylic ring expansion in alkyne reactions and to develop a new general route for the preparation of N-heteroaromatics. This method utilizes alkenes as synthetic equivalents of alkynes by coupling homoallylic ring expansion to yield the formal "6-endo" products with aromatization via stereoelectronically assisted C-C bond scission. Computational analysis of the homoallyic expansion potential energy surface reveals that the indirect 5-exo/3-exo/retro-3-exo path is faster than the direct 6-endo-trig closure, revealing the general exo-preference for the cyclization processes.

show abstract

“…[61] In this context, In 2015, Alabugin and coworkers successfully established the synthesis of heterocycles from o-alkenyl arylisonitriles via radical 6-endo-trig cyclization. [62] (Scheme 8a) They have started the initial reaction using Bn substituted alkene, 19 (1-isocyano-2-(3-phenylprop-1-en-1-yl) benzene) with boronic acid in the presence of Manganese(III) acetylacetonate catalyst, refluxed under toluene to furnish the desired quinoline product, 20 in excellent yields. The plausible reaction mechanism is outlined in (Scheme 8b).…”

Section: Radical Addition/cyclizationsmentioning

confidence: 99%

“…One is direct 6-endo-trig radical cycloaddition at the C2 position of o-alkenyl isocyanide, and Another is 5-exo-trig addition via 3-exo and retro-3-exo-trig reaction sequence. [62] The authors suggested 6-endo-trig radical cycloaddition is more favorable to lead intermediate E, [76] then the reaction further proceeds to afford corresponding 4-CN-2-CF 3 -containing quinoline product via another SET process and deprotonation.…”

Section: Radical Addition/cyclizationsmentioning

confidence: 99%

Radical Transformations towards the Synthesis of Quinoline: A Review

Teja

Khan

2020

Chemistry An Asian Journal

View full text Add to dashboard Cite

Quinoline is considered one of the most ubiquitous heterocycles due to its engaging biological activities and synthetic utility over organic transformations. Over the past few decades, numerous reports have been documented in the synthesis of quinolines. The classical methods including, Skraup, Friedlander, Doebner‐von‐Miller, Conrad‐Limpach, Pfitzinger quinoline synthesis, and so forth, these are the well‐known methods to construct principal quinoline scaffold with several advantages and limitations. Recently, radical insertion or catalyzed reactions have emerged as a powerful and efficient tool to construct heterocycles with high atom efficiency and step economy. In this concern, this minireview mainly focused on the developments of Quinoline synthesis via radical reactions. In addition, a brief description of the preparation procedure, reactivity, and mechanisms is also included, where as possible. Respectively, the synthesis of quinolines is classified and summarized based on its reactivity, so it will help the researchers to grab the information in this exploration area, as Quinolines are promising pharmacophores.

show abstract

Coupling cyclizations with fragmentations for the preparation of heteroaromatics: quinolines from o-alkenyl arylisocyanides and boronic acids

Cited by 55 publications

References 48 publications

(Hetero)aromatics from dienynes, enediynes and enyne–allenes

(Hetero)aromatics from dienynes, enediynes and enyne–allenes

Coupling Radical Homoallylic Expansions with C–C Fragmentations for the Synthesis of Heteroaromatics: Quinolines from Reactions of o-Alkenylarylisonitriles with Aryl, Alkyl, and Perfluoroalkyl Radicals

Radical Transformations towards the Synthesis of Quinoline: A Review

Contact Info

Product

Resources

About