Morita–Baylis–Hillman‐Type [3,3]‐Rearrangement: Switching from<i>Z</i>‐ to<i>E</i>‐Selective α‐Arylation by New Rearrangement Partners

Zhang, Lei; Bao, Wangzhen; Liang, Yuchen; Pan, Wenjing; Li, Dongyang; Kong, Lichun; Wang, Zhixiang; Peng, Bo

doi:10.1002/ange.202100497

Cited by 3 publications

(1 citation statement)

References 76 publications

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“…investigated the reaction of PhI(OAc) 2 with α,β‐unsaturated oxazoline derivatives mediated by TMSOTf in the formation of aryl iodanes. Subsequent base promoted an enolate‐iodonium rearrangements in the synthesis of a wide variety of valuable α‐aryl α, β‐unsaturated oxazolines [30] . The remaining iodide atom in the products allowed for elaborating alkenes with a boryl group or vinyl ester moieties, as well as incorporating an alkynyl group into phenyl ring for several important synthons.…”

Section: Claisen‐rearrangementmentioning

confidence: 99%

Synthesis of Versatile Aryliodine Synthons by Aryliodonium Rearrangement Reactions

Pan,

Wang,

Han

2024

Asian J Org Chem

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The excellent reactivity of diaryliodonium salts has primarily been attributed to the efficient departure of the iodoarene unit, facilitating a variety of arylation reactions. However, one equivalent of iodoarene as a side‐product is a chemical waste in these reactions, which was criticized by chemists for hindering its popularity. Recently, the development of synthetic methodology that preserve the aryl iodine moiety received increasing attention. Oxidative rearrangement reactions involving aryliodonium reagents have significantly addressed the atom‐economic issue, thereby broadening the reaction scope. The resulting intricate aryliodine products are viewed as valuable synthons for the synthesis of natural products, pharmaceutical intermediates and other fine chemicals.

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Section: Claisen‐rearrangementmentioning

confidence: 99%

Synthesis of Versatile Aryliodine Synthons by Aryliodonium Rearrangement Reactions

Pan,

Wang,

Han

2024

Asian J Org Chem

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Sigmatrope [1,5]‐Kohlenstoffverschiebung transienter C3‐Ammoniumenolate

et al. 2022

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Die stereospezifische [1,5]-Kohlenstoffverschiebung der C3-Ammoniumenolate wird beschrieben. Gemäß mechanistischen, kinetischen und rechnergestützten Experimenten verläuft die neuartige Umlagerung über ein transientes C3-Ammoniumenolat. Dies wird durch eine katalysierte intramolekulare Aza-Michael-Addition erzeugt. Die anschließende [1,5]-sigmatrope Kohlenstoffmigration bildet die entsprechenden Tetrahydrochinolin-4-one in 61-98 % Ausbeute und mit exzellenten Diastereoselektivitäten von d.r. > 99 : 1.

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Sigmatropic [1,5] Carbon Shift of Transient C3 Ammonium Enolates

et al. 2022

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The stereospecific sigmatropic [1,5] carbon shift of C3 ammonium enolates is discovered. According to mechanistic, kinetic and computational experiments, this new rearrangement proceeds via the catalytic generation of a transient C3 ammonium enolate by intramolecular aza-Michael addition. This intermediate rapidly undergoes [1,5] sigmatropic carbon migration to furnish the respective tetrahydroquinoline-4-ones with excellent diastereoselectivities of d.r. > 99 : 1 and in 61-98 % yield.Rearrangement reactions are one of the most useful tools for construction of organic scaffolds. [1] In fact, [1,2] [2] and [3,3] [3] sigmatropic rearrangements are typical reactions used to achieve molecular complexity with high stereocontrol. Observations of sigmatropic shifts of hydrogen, silicon or acyl groups across extended π-systems, such as cyclopentadiene, indenyl [4] or quinone [4d, 5] structures, have provided a basis for in-depth understanding of organic chemistry [6] in addition to the synthetic benefits. Electrophilic nitrogenylide rearrangements, like the [1,2] and [2,3] Stevens [7] and Sommelet-Hauser [8] rearrangements, offer stereoselective access to synthetically useful amino building blocks through nitrogen to carbon chirality transfer. [9] The [1,2] Stevens progresses by homolytic CÀ N bond dissociation with formation of a caged radical pair, while the [2,3] Stevens and the Sommelet-Hauser rearrangements proceed by a concerted mechanism (Scheme 1a and b).Both rearrangements require, first, quaternization of the nitrogen atom and, as a second step, formation of the ylide by deprotonation. There have been only a few reported examples of catalytic creation of the ylide intermediate. [10] And although C3 ammonium enolates [11] are well-known intermediates in aza-Michael and Morita-Baylis-Hillman reactions, [12] cyclic C3 ammonium enolates have yet to be considerd as precursors for sigmatropic [1,5] rearrangements (Scheme 1c).

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Morita–Baylis–Hillman‐Type [3,3]‐Rearrangement: Switching fromZ‐ toE‐Selective α‐Arylation by New Rearrangement Partners

Cited by 3 publications

References 76 publications

Synthesis of Versatile Aryliodine Synthons by Aryliodonium Rearrangement Reactions

Synthesis of Versatile Aryliodine Synthons by Aryliodonium Rearrangement Reactions

Sigmatrope [1,5]‐Kohlenstoffverschiebung transienter C3‐Ammoniumenolate

Sigmatropic [1,5] Carbon Shift of Transient C3 Ammonium Enolates

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