Stereocontrolled Addition of Scrambling <i>ortho</i>-Sulfinyl Carbanions: Easy Access to Homopropargylamines and α-Allenylamines

Cruz-Delgado, Balú; Rodríguez, Ricardo I.; Rosado‐Abón, Anielka; Sánchez‐Obregón, Rubén; Yuste, Francisco; Alemán, José V.

doi:10.1021/acs.orglett.0c00625

Cited by 5 publications

(2 citation statements)

References 42 publications

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“…Vinylogous Mannich-type reactions have been identified as very important tools in the synthesis of alkaloids and man-made bioactive nitrogen-containing compounds. − However, their variants, alkynylogous Mannich-type reactions have been neglected for a long time . As a matter of fact, such reactions offer highly functionalized products, α-allenylamines, − which bear a synthetically useful allene unit, − a protected amine unit, and a versatile carbonyl group. As in vinylogous Mannich-type reactions, one of the challenging issues in alkynylogous Mannich-type reactions is the achievement of required γ-addition with high regioselectivity.…”

Section: Introductionmentioning

confidence: 99%

Copper(I)-Catalyzed Asymmetric Synthesis of α-Allenylamines and β-Lactams through Regioselective Mannich-Type Reactions

et al. 2022

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Herein, a copper(I)-catalyzed alkynylogous Mannich-type reaction is developed, which starts from pyrazoleamides of alkynyl-substituted acetic acids and provides an array of chiral α-allenylamine derivatives in high regio-, diastereo-, and enantioselectivities. This reaction enjoys broad substrate scopes on both pyrazoleamides and N-Boc-aldimines. Moreover, a copper(I)-catalyzed cascade cyclization of pyrazoleamides of but-2-ynoic acid is disclosed, which involves an α-selective Mannich-type reaction as a key step and delivers a series of chiral β-lactams containing a pyrazole moiety in high enantioselectivity. In light of some mechanism studies, the deprotonation step is found as the rate-determining step in this cyclization. Propargyl copper(I) species are proposed as the operating nucleophiles in both reactions. Finally, the synthetic utility of the alkynylogous product is demonstrated by the transformations of the product to chiral α,β-unsaturated lactones. Furthermore, a gram-scale preparation of chiral β-lactam and its following transformations proved its synthetic versatility.

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Section: Introductionmentioning

confidence: 99%

Copper(I)-Catalyzed Asymmetric Synthesis of α-Allenylamines and β-Lactams through Regioselective Mannich-Type Reactions

et al. 2022

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“…These methods generate a stereocenter α to the nitrogen atom. In contrast, very few catalytic methods have emerged only recently to prepare homopropargyl amine with a β-stereogenic center. , Hu and co-workers reported the construction of acyclic homopropargyl amine with a β quaternary stereocenter through an elegant multicomponent strategy . In these methods, , the alkynyl group needs to be preinstalled into the prochiral carbon of the substrate to facilitate subsequent formation of the alkynylated stereocenter.…”

Section: Introductionmentioning

confidence: 99%

Ir-Catalyzed Regio- and Enantioselective Hydroalkynylation of Trisubstituted Alkene to Access All-Carbon Quaternary Stereocenters

Zhang

2021

J. Am. Chem. Soc.

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The stereoselective construction of all-carbon quaternary stereocenters, especially acyclic ones, represents an important challenge in organic synthesis. In particular, homopropargyl amides with a quaternary stereocenter β to a nitrogen atom are valuable synthetic intermediates, which could be transformed to diverse chiral structures through alkyne transformations. However, highly enantioselective synthetic methods for homopropargyl amides with a β quaternary stereocenter are extremely rare. We report here unprecedented substrate-directed, iridium-catalyzed enantioselective hydroalkynylations of trisubstituted alkenes to form an acyclic all-carbon quaternary stereocenter β to a nitrogen atom. The hydroalkynylation of enamide occurred with unconventional selectivity, favoring the more hindered reaction site. Homopropargyl amides with β-stereocenters were prepared in high regio- and enantioselectivities. Combined experimental and computational studies revealed the origin of the regio- and enantioselectivities.

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Stereocontrolled synthesis of tetrasubstituted chiral allenes by a Michael Addition of ortho-sulfinylated benzyl-propargylic carbanions

Venegas-Nava

Yuste

Sánchez‐Obregón

2021

Tetrahedron Letters

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Stereocontrolled Addition of Scrambling ortho-Sulfinyl Carbanions: Easy Access to Homopropargylamines and α-Allenylamines

Cited by 5 publications

References 42 publications

Copper(I)-Catalyzed Asymmetric Synthesis of α-Allenylamines and β-Lactams through Regioselective Mannich-Type Reactions

Copper(I)-Catalyzed Asymmetric Synthesis of α-Allenylamines and β-Lactams through Regioselective Mannich-Type Reactions

Ir-Catalyzed Regio- and Enantioselective Hydroalkynylation of Trisubstituted Alkene to Access All-Carbon Quaternary Stereocenters

Stereocontrolled synthesis of tetrasubstituted chiral allenes by a Michael Addition of ortho-sulfinylated benzyl-propargylic carbanions

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