Catalytic Dearomative Spirocyclization via Gold Carbene Species Derived from Ynamides: Efficient Synthesis of 2‐Azaspiro[4.5]decan‐3‐ones

Ito, Mamoru; Kawasaki, Ryo; Kanyiva, Kyalo Stephen; Shibata, Takanori

doi:10.1002/chem.201800314

Cited by 18 publications

(12 citation statements)

References 53 publications

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“…The addition of a methyl substituent was sufficient to direct the reaction solely to the cycloheptatriene‐fused lactam 8 f in preparatively useful yield (Scheme ). The allyl enol ether 8 g was also formed despite the potential for fragmenting spirocyclisation on elimination of an allyl cation from a cationic Wheland intermediate . Use of ortho ‐substituted substrates affords the 7‐substituted products 8 h / i .…”

Section: Methodsmentioning

confidence: 99%

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A Gold Carbene Manifold to Prepare Fused γ‐Lactams by Oxidative Cyclisation of Ynamides

Sánchez-Cantalejo

Priest

Davies

2018

Chemistry A European J

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Gold‐catalysed oxidative cyclisation reactions of ynamides offer great promise in γ‐lactam synthesis but are limited by preferential over‐oxidation to form α‐keto imides. Evaluating the factors that might limit N‐cyclisation pathways led to effective gold‐catalysed conditions that allow access to different fused γ‐lactams on changing the ynamide N‐substituent and accommodate previously incompatible substitution patterns. New and efficient methods for the synthesis of functionalised 3‐aryl indoles and cyclohepta[c]pyrrol‐1‐one derivatives are presented. These conditions illustrate the complementarity of gold catalysis to other metals.

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Section: Methodsmentioning

confidence: 99%

“…Formation of the oxindole 3 l is noteworthy as electron‐donating ynamide substituents such as the p ‐methoxybenzene group were either not tolerated or not assessed in diverse ynamide oxidation processes (Scheme ) ,,,. Steric bulk at the ortho ‐positions of both substituents can also be accommodated ( 3 f / k ).…”

Section: Methodsmentioning

confidence: 99%

A Gold Carbene Manifold to Prepare Fused γ‐Lactams by Oxidative Cyclisation of Ynamides

Sánchez-Cantalejo

Priest

Davies

2018

Chemistry A European J

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“…The reaction is believed to proceed via spirocyclization of the aryloxy moiety onto an α-oxo gold carbenoid intermediate 159. 93 Hydrolysis of oxonium 160 followed by protodemetalation allows for the formation of lactam 158 (Scheme 38). This method proved to be robust, efficient (22−98%), and demonstrated good substrate tolerance.…”

Section: Ynamidesmentioning

confidence: 99%

Gold-Catalyzed Reactions of Specially Activated Alkynes, Allenes, and Alkenes

et al. 2020

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This review describes the gold-catalyzed reactions of specially activated alkynes, allenes, and alkenes. Such species are characterized by the presence of either electron-donating or electron-withdrawing groups as substituents of the carbon π-system. They are intrinsically polarized, and when compared to their nonspecially activated counterparts can therefore be involved in gold-catalyzed transformations featuring increased regio-, stereo-, and chemoselectivities. The chemistry of specially activated carbon π-systems under homogeneous gold catalysis is extremely rich and varied. The reactivity observed with nonspecially activated unsaturated systems can often be transposed to specially activated ones without loss of efficiency. However, specially activated carbon π-systems also exhibit specific reactivities that cannot be attained with regular substrates. In this family of carbon π-systems, ynamides and their analogs, along with alkynyl carbonyl derivatives, are the classes of substrates that have retained the most attention. This review provides an overview of the chemistry developed with all classes of specially activated carbon π-systems by discussing their general and specific reactivities, presenting and commenting on their gold-catalyzed transformations as well as their applications.

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“…[42] Following a general approach towards functionalization of α-oxo gold carbenoid intermediates via an S E Ar reactivity of ynamides bearing aryl groups on the nitrogen atom, an intramolecular catalytic dearomatization of phenols via gold carbene species was reported by Shibata group to provide 2azaspiro[4.5]decan-3-ones 76 (Scheme 39). [43] The salient features of this reaction are the use of NHC ligand and water as co-solvent. Moreover, the reaction does not require hazardous diazo compounds as carbene precursors.…”

Section: Combination Of O-based Nucleophiles and Gold Keteniminium Speciesmentioning

confidence: 99%

Gold‐Catalyzed Transformation of Ynamides

Shandilya

Gogoi

Dutta

et al. 2021

The Chemical Record

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Ynamide, a unique species with inherited polarization of nitrogen lone pair electron to triple bond, has been largely used for the developement of novel synthetic methods and the construction of unusual N-bearing heterocycles. The reaction versatility of ynamide on umpolung reactivity, radical reactions and asymmetric synthesis have been recently reviewed. This review provides an overall scenic view into the gold catalyzed transformation of ynamides. The ynamides reactivity towards nitrogen-transfer reagents, such as azides, nitrogen ylides, isoxazoles, and anthranils; oxygen atom-transfer reagents, like nitrones, sulfoxides, and pyridine N-oxides; and carbon nucleophiles under gold catalysis are herein uncovered. The scope as well the mechanistic insights of each reaction is also briefed.

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Catalytic Dearomative Spirocyclization via Gold Carbene Species Derived from Ynamides: Efficient Synthesis of 2‐Azaspiro[4.5]decan‐3‐ones

Cited by 18 publications

References 53 publications

A Gold Carbene Manifold to Prepare Fused γ‐Lactams by Oxidative Cyclisation of Ynamides

A Gold Carbene Manifold to Prepare Fused γ‐Lactams by Oxidative Cyclisation of Ynamides

Gold-Catalyzed Reactions of Specially Activated Alkynes, Allenes, and Alkenes

Gold‐Catalyzed Transformation of Ynamides

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