Palladium catalyzed stereospecific Michael arylation of 6-alkyl-5,6-dihydro-2H-pyran-2-ones

Stokker, G. E.

doi:10.1016/s0040-4039(00)95465-0

Cited by 49 publications

(14 citation statements)

References 6 publications

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“…In the cases where an amine bearing a and b hydrogen atoms is used as a coreagent or co-catalyst in the reaction mixture, unexpected isomerisations and/or reductions are sometimes observed [1]. A rationale for this behaviour has been proposed which relies on the formation of a palladium hydride-iminium (or imine) complex, in equilibrium with the corresponding enamine complex.…”

Section: Introductionmentioning

confidence: 99%

Pd–H from Pd/C and triethylamine: Implications in palladium catalysed reactions involving amines

Coquerel

Brémond

Rodríguez

2007

Journal of Organometallic Chemistry

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Section: Introductionmentioning

confidence: 99%

Pd–H from Pd/C and triethylamine: Implications in palladium catalysed reactions involving amines

Coquerel

Brémond

Rodríguez

2007

Journal of Organometallic Chemistry

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“…The lactone could be converted into the spirolactam 12 by treating 7 i with benzylamine under acidic conditions, and it was also possible to retain the lactone and provide access to the saturated δ‐lactone by reducing the enol. To this end, hydrogenation of dihydropyranone 7 z led to tetrahydropyranone 13 , which is the penultimate intermediate in the synthesis of a platelet aggregation inhibitor that was previously accessed only in racemic form . It should be noted that the optical purity of the starting materials is retained in each of the products.…”

Section: Methodsmentioning

confidence: 99%

Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis

Mishra

Aponick

2019

Angewandte Chemie

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In this work, we report enantioselective orthogonal tandem catalysis for the one pot conversion of Meldrum's acid derivatives and alkynes into δ‐lactones. This new transformation, which resembles a formal [4+2] cycloaddition with concomitant decarboxylation and loss of acetone, proceeds in high yields and excellent enantioselectivity (up to 99 % ee) over a broad substrate scope. The products are densely functionalized and ripe for further transformations, as demonstrated here by both ring‐opening reactions and reduction to saturated lactones. It was discovered that a new and serendipitously formed AgI‐Me‐StackPhos complex efficiently catalyzes the highly selective 6‐endo‐dig cyclization, completely reversing the regiochemistry that has been previously reported in related systems. More generally, in this study we identify a pair of compatible catalysts for alkyne difunctionalization that operate concurrently, which enable the alkyne to act as both a nucleophile and an electrophile in sequential one‐pot transformations.

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“…[33] It should be noted that the optical purity of the starting materials is retained in each of the products. The lactone in 7b was readily opened to form the keto Weinreb amide 9 in 95 %y ield.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…To this end, hydrogenation of dihydropyranone 7z led to tetrahydropyranone 13,w hich is the penultimate intermediate in the synthesis of ap latelet aggregation inhibitor that was previously accessed only in racemic form. [33] It should be noted that the optical purity of the starting materials is retained in each of the products. These facile transformations are enabled by the presence of the enol lactone functional group that is efficiently incorporated using this chemistry to effectively provide al atent ketone in the product, and many other types of transformations could be envisioned.…”

Section: Angewandte Chemiementioning

confidence: 99%

Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis

Mishra

Aponick

2019

Angew Chem Int Ed

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In this work, we report enantioselective orthogonal tandem catalysis for the one pot conversion of Meldrumsacid derivatives and alkynes into d-lactones.T his new transformation, whichr esembles af ormal [4+ +2] cycloaddition with concomitant decarboxylation and loss of acetone,p roceeds in high yields and excellent enantioselectivity (up to 99 %ee) over ab road substrate scope.T he products are densely functionalized and ripe for further transformations,asdemonstrated here by both ring-opening reactions and reduction to saturated lactones.I tw as discovered that an ew and serendipitously formed Ag I -Me-StackPhos complex efficiently catalyzest he highly selective 6-endo-dig cyclization, completely reversing the regiochemistry that has been previously reported in related systems.M ore generally,i nt his study we identify ap air of compatible catalysts for alkyne difunctionalization that operate concurrently,w hich enable the alkyne to act as both an ucleophile and an electrophile in sequential one-pot transformations.Scheme 1. Enantio-and regioselective orthogonal tandem catalysis.

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Palladium catalyzed stereospecific Michael arylation of 6-alkyl-5,6-dihydro-2H-pyran-2-ones

Cited by 49 publications

References 6 publications

Pd–H from Pd/C and triethylamine: Implications in palladium catalysed reactions involving amines

Pd–H from Pd/C and triethylamine: Implications in palladium catalysed reactions involving amines

Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis

Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis

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