α-Iminol Rearrangement Triggered by Pd-Catalyzed C–H Addition to Nitriles Sequences: Synthesis of Functionalized α-Amino Cyclopentanones

Cheng, Na; Cui, Shu-Qiang; Ma, Qianqian; Wei, Zhonglin; Liao, Wei‐Wei

doi:10.1021/acs.orglett.0c04214

Cited by 13 publications

(7 citation statements)

References 44 publications

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“…Although rare, α-ketol rearrangements have been included in the total syntheses of some natural products with high success. In the first total synthesis of periconianone A (31), an α-ketol rearrangement was used to shift a four-carbon chain one position on the bicyclic molecule 32 using the base calcium methoxide with a yield of 70% of 33 and a diastereomeric ratio of 3:1 (14:1 after separation) (Figure 8) [11]. Note that 33 bears an enone moiety, and therefore, this reaction is apparently the first example of the use of conjugation to drive an α-ketol rearrangement.…”

Section: α-Ketol Rearrangements Implemented In Total Synthesesmentioning

confidence: 99%

“…Interestingly, another tandem sequence that exploits the relief of ring strain from cyclobutane derivatives has been developed by Cheng et al to prepare functionalized α-amino cyclopentanones [ 31 ]. In the presence of a palladium catalyst, an electron-rich heteroarene 115 first adds to the nitrile group in a 1-cyanocyclobutyl ester 116 to give a tetrahedral imine intermediate 117 .…”

Section: Reviewmentioning

confidence: 99%

“…Alternative heteroarenes were much poorer, with pyrroles and thiophenes giving yields of ≈20% or less and benzofuran and benzothiophene failing to produce any product. Interestingly, a cyclopentanone-derived substrate ( 120 ) failed to yield the corresponding α-amino cyclohexanone 121 under the standard conditions used for cyclobutane derivatives ( Figure 21b ), highlighting the importance of the relief of ring strain in driving the rearrangement [ 31 ].…”

Section: Reviewmentioning

confidence: 99%

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α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

Benz¹,

Murkin²

2021

Beilstein J. Org. Chem.

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In the presence of a suitable acid or base, α-hydroxyaldehydes, ketones, and imines can undergo isomerization that features the 1,2-shift of an alkyl or aryl group. In the process, the hydroxy group is converted to a carbonyl and the aldehyde/ketone or imine is converted to an alcohol or amine. Such α-ketol/α-iminol rearrangements are used in a wide variety of synthetic applications including asymmetric synthesis, tandem reactions, and the total synthesis and biosynthesis of natural products. This review explores the use of α-ketol rearrangements in these contexts over the past two decades.

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Section: α-Ketol Rearrangements Implemented In Total Synthesesmentioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

See 1 more Smart Citation

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

Benz¹,

Murkin²

2021

Beilstein J. Org. Chem.

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“…The electronic nature of the substituent has no significant influence on the yield of the reaction ( 184 – 186 ). With bulky alkyl groups ( 201 and 202 ) no reaction takes place [ 33 ].…”

Section: Synthetic Applicationsmentioning

confidence: 99%

“…The electronic nature of the substituent has no significant influence on the yield of the reaction (184-186). With bulky alkyl groups (201 and 202) no reaction takes place [33]. This method can also be applied to oxazole substituted heterocycles to produce bisoxazole derivatives in moderate yields.…”

Section: Synthesis Of 2-aminocyclopentanones and 2-amino-4-azacyclopentanonesmentioning

confidence: 99%

Recent Advances on O-Ethoxycarbonyl and O-Acyl Protected Cyanohydrins

2021

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Ethoxycarbonyl cyanohydrins and O-acyl cyanohydrins are examples of O-protected cyanohydrins in which the protecting group presents an electrophilic center, contributing to additional reaction pathways. The first section of this review describes recent advances on the synthesis of O-ethoxycarbonyl and O-acyl protected cyanohydrins. Reactions using KCN or alkyl cyanoformates as the cyanide ion source are described, as well as organic and transition metal catalysis used in their preparation, including asymmetric cyanation. In a second part, transformations, and synthetic applications of O-ethoxycarbonyl/acyl cyanohydrins are presented. A variety of structures has been obtained starting from such protected cyanohydrins and, in particular, the synthesis of oxazoles, 1,4-diketones, 1,3-diketones, 2-vinyl-2-cyclopentenones through various methods are discussed.

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Asymmetric Construction of α,α‐Disubstituted Piperazinones Enabled by Benzilic Amide Rearrangement

Quan

et al. 2023

Angewandte Chemie

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An unprecedent asymmetric catalytic benzilic amide rearrangement for the synthesis of α,α‐disubstituted piperazinones is reported. The reaction proceeds via a domino [4+1] imidazolidination/formal 1,2‐nitrogen shift/1,2‐aryl or alkyl migration sequence, employing readily available vicinal tricarbonyl compounds and 1,2‐diamines as starting materials. This approach provides an efficient access to chiral C3‐disubsituted piperazin‐2‐ones with high enantiocontrol, which are exceedingly difficult to access from the existing synthetic methodologies. The observed enantioselectivity was proposed to be controlled by dynamic kinetic resolution in the 1,2‐aryl/alkyl migration step. The resulting densely functionalized products are versatile building blocks to bioactive natural products, drug molecules and their analogues.

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α-Iminol Rearrangement Triggered by Pd-Catalyzed C–H Addition to Nitriles Sequences: Synthesis of Functionalized α-Amino Cyclopentanones

Cited by 13 publications

References 44 publications

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

Recent Advances on O-Ethoxycarbonyl and O-Acyl Protected Cyanohydrins

Asymmetric Construction of α,α‐Disubstituted Piperazinones Enabled by Benzilic Amide Rearrangement

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