Synthesis of β-Nitro Ketone from Geminal Bromonitroalkane and Silyl Enol Ether by Visible Light Photoredox Catalysis

Various β-nitro ketones, including those bearing a β-tertiary carbon, were prepared from geminal bromonitroalkanes and trimethylsilyl enol ethers of a broad range of ketones under visible light photoredox catalysis, which...

A Convenient Approach towards the Synthesis of ADMDP Type Iminosugars and Nojirimycin Derivatives from Sugar-Derived Lactams

An efficient method for the synthesis of nojirimycin- and pyrrolidine-based iminosugar derivatives has been developed. The strategy is based on the partial reduction in sugar-derived lactams by Schwartz’s reagent and tandem stereoselective nucleophilic addition of cyanide or a silyl enol ether dictated by Woerpel’s or diffusion control models, which affords amino-modified iminosugars, such as ADMDP or higher nojirimycin derivatives.

An Access to Highly Enantioenriched cis-3,5-Disubstituted γ-Lactones from α-Bromoacetate and Silyl Enol Ether

A novel synthetic strategy for highly enantioenriched cis-3,5-disubstituted γ-lactones has been developed by the AgOTf-promoted nucleophilic substitution of α-bromoacetates with silyl enol ethers and subsequent reductive lactonization. The utility of...

Photocatalytic Decarboxylative Alkylation of Silyl Enol Ether and Enamide with N-(Acyloxy)phthalimide using Ammonium Iodide

Enamides and silyl enol ethers were alkylated to deliver products of N-acyl imines and ketones in the presence of a catalytic amount of N-tetrabutylammonium iodide under irradiation of purple light...

7-Siloxy-Substituted Hexahydronaphthalene Derivatives: Samarium Diiodide Promoted Synthesis and Typical Reactions

The samarium diiodide promoted reductive cyclization of a series of γ-aryl ketones with acetoxy, alkoxy, and siloxy groups in ortho-, meta-, and para-positions was investigated. Only precursors with p-acetoxy, p-tert-butoxy, or p-siloxy substituents furnished decent yields of the desired 7-oxy-1,2,3,4,6,8a-hexahydronaphthalene derivatives. The products were formed without contamination with the regio­isomeric bicyclic products containing conjugated double bonds. Typical reactions exploiting the silyl enol ether moiety of the 7-(tert-butyl­dimethylsiloxy)-1,2,3,4,6,8a-hexahydronaphthalene derivative were performed, allowing stereoselective access to highly substituted hexahydro­-, octahydro-, or decahydronaphthalene derivatives.

A Catalytic Asymmetric Ene Reaction for Direct Preparation of α-Hydroxy 1,4-Diketones as Intermediates in Natural Product Synthesis

Asymmetric access to α-hydroxy-1,4-diketones has been achieved by direct ene coupling of silyl enol ethers with glyoxal electrophiles, mediated by a chiral N,N′-dioxide–nickel(II) complex catalyst. Successful union of a polyketide silyl enol ether with an α-quaternary glyoxal, generated by dioxirane oxidation of an α-diazo ketone, models a proposed C5–C6 disconnection of the polyketide and spirocyclic imine domains of the marine natural product, portimine.

The Dianion of Dehydroacetic Acid: A Direct Synthesis of Pogopyrone A

Dehydroacetic acid was converted into a silyl enol ether and titanium enolate. These reacted effectively with aldehydes and N-bromosuccinimide. Oxidation of the adduct with benzaldehyde afforded pogopyrone A in excellent overall yield.

Oxovanadium(v)-catalyzed oxidative cross-coupling of enolates using O2 as a terminal oxidant

The oxovanadium(v)-catalyzed oxidative cross-coupling of enolates using O2 as a terminal oxidant is reported, where a boron enolate and a silyl enol ether were employed as enolates.

Preparation and facile addition reactions of iminium salts derived from amino ketene silyl acetal and amino silyl enol ether

While iminium salts generated from amino ketene silyl acetals react with silyl enol ethers, those from amino silyl enol ethers also undergo facile addition reactions to give alpha-amino ketone derivatives in good yields.