Organocatalytic Asymmetric Synthesis of Cyclic Acetals with Spirooxindole Skeleton

An organocatalytic asymmetric synthesis of cyclic acetal with spirooxindole skeleton has been developed via a domino reaction between isatin and γ-hydroxy enones. Bifunctional squaramide catalyst with adamantyl motif was found to be the most effective for the cascade reaction. With 10 mol% of the catalyst, the desired products were obtained in 1.8:1...

2d

From Stoichiometric Reagents to Catalytic Partners: Selenonium Salts as Alkylating Agents for Nucleophilic Displacement Reactions in Water

The ability of chalcogenium salts to transfer an electrophilic moiety to a given nucleophile is well known. However, up to date these reagents have been used in stoichiometric quantities, producing a substantial amount of waste as by-products of the reaction. In this report, we disclose further investigation of selenonium salts as S-adenosyl-L-methionine...

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Photocatalytic Atom‐Transfer Radical Addition of Activated Chlorides to Alkenes

A protocol for performing atom transfer radical addition of activated alkyl chlorides to alkenes is described. The reaction is promoted by blue light in the presence of an organic photocatalyst (3DPA2FBN) serving to generate free radicals, and a copper complex (IMesCuCl), which facilitates the chlorine transfer step. The reaction works efficiently with...

2d

Enantioselective nitro‐Michael Addition Catalyzed by N‐terminal Guanidinylated Helical Peptide

Enantioselective Michael addition of β-dicarbonyl compounds toward nitroalkenes were realized by using an immobilized, N-terminal-guanidinylated peptide, NH₂-(NH=)C-Trp-Trp-(Leu-Leu-Aib)₃-PEG-PS-resin (Aib = 2-aminoisobutyric acid), as catalyst. Viable nucleophiles were acetylacetone, dimethyl malonate,...

2d

Transannulation of Pyridotriazoles with Naphthoquinones and Indoles: Synthesis of Benzo[<i>f</i>]pyrido[1,2‐<i>a</i>]indoles and Indolizino[3,2‐<i>b</i>]indoles

Ruthenium catalysed denitrogenative transannulation of pyridotriazoles with naphthoquinones provided the transannulated benzo[<i>f</i>]pyrido[1,2-<i>a</i>]indoles derivatives in good to excellent yields. While pyridotriazoles with indoles in presence of PivOH and oxone yield indolizino[3,2-<i>b</i>]indoles under metal-free...

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Pd‐Catalyzed Asymmetric Addition of Arylboronic Acids to Pyrazolinone Ketimines

An asymmetric addition of arylboronic acids to pyrazolinone ketimines is reported using palladium/chiral N,N′-disulfonyl bisimidazoline (Bim) catalytic system, producing 25 examples of enantioenriched 4-amino-5-pyrazolones bearing one quaternary carbon stereocenter with 60-91% yields and 81-98% ee. The reaction demonstrates remarkable compatibility...

2d

Brønsted Acid Catalyzed (3+2)‐Cycloaddition of Thioketones and Indole‐2‐carbinols Toward Thiazolo[3,4‐a]indoles

Herein, we report a Brønsted acid catalyzed approach to access the yet unknown heterocyclic motif of thiazolo[3,4-a]indoles in a one-pot reaction under very mild conditions. A broad range of thiazolo[3,4-a]indoles was generated from indole-2-methanols and thioketones with 45-99% yield and good functional group tolerance. The practicality of the process...

2d

Asymmetric addition and cycloaddition reactions with ylidene‐five‐membered heterocycles

Five-membered heterocycles bearing an exocyclic double bond have been successfully used as substrates in asymmetric addition and cycloaddition reactions. Ylidene-heterocycles are attractive substrates due to its high functionalisation and the presence of an electrophilic conjugated exocyclic double bound that can participate in nucleophilic addition...

2d

Single Electron Transfer‐Induced Selective α˗Oxygenation of Glycine Derivatives

Modification of amino acids is an important strategy in organic and bioorganic chemistry. In contrast to common side-chain functionalization, backbone modification is much less explored. Especially glycine units seem to be attractive and versatile since a wide range of functionality can be potentially introduced. We report here oxidative modification...

3d

Asymmetric addition and cycloaddition reactions with ylidene‐five‐membered heterocycles

Five-membered heterocycles bearing an exocyclic double bond have been successfully used as substrates in asymmetric addition and cycloaddition reactions. Ylidene-heterocycles are attractive substrates due to its high functionalisation and the presence of an electrophilic conjugated exocyclic double bound that can participate in nucleophilic addition...

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