Palladium-Catalyzed Addition of Aryl Halides to -Sulfinylamines for the Synthesis of Sulfinamides.

Sulfinamides are versatile, synthetically useful intermediates, and final motifs. Traditional methods to synthesize sulfinamides generally require substrates with preinstalled sulfur centers. However, these precursors have limited commercial availability, and the associated synthetic routes often require harsh reaction conditions and highly reactive reagents, thus severely limiting their application.

Reactivity and selectivity modulation within a molecular assembly: recent examples from photochemistry.

In recent years, photochemical reactions have emerged as powerful transformations which significantly expand the repertoire of organic synthesis. However, a certain lack of selectivity can hamper their application and limit their scope. In this context, a major research effort continues to focus on an improved control over stereo- and chemoselectivity that can be achieved in molecular assemblies between photosubstrates and an appropriate host molecule.

Enantioselective [2 + 2] Photocycloaddition via Iminium Ions: Catalysis by a Sensitizing Chiral Brønsted Acid.

,-Acetals derived from α,β-unsaturated β-aryl substituted aldehydes and (1-aminocyclohexyl)methanol were found to undergo a catalytic enantioselective [2 + 2] photocycloaddition to a variety of olefins (19 examples, 54-96% yield, 84-98% ). The reaction was performed by visible light irradiation (λ = 459 nm). A chiral phosphoric acid (10 mol %) with an ()-1,1'-bi-2-naphthol (binol) backbone served as the catalyst.

Morpholine Ketene Aminal as Amide Enolate Surrogate in Iridium-Catalyzed Asymmetric Allylic Alkylation.

Morpholine ketene aminal is employed in iridium-catalyzed asymmetric allylic alkylation reactions as a surrogate for amide enolates to prepare γ,δ-unsaturated β-substituted morpholine amides. Kinetic resolution or, alternatively, stereospecific substitution affords the corresponding products in high enantiomeric excess. The utility of the products generated by this method has been showcased by their further elaboration into amines, ketones, or acyl silanes.

Trimethyl Orthoacetate and Ethylene Glycol Mono-Vinyl Ether as Enolate Surrogates in Enantioselective Iridium-Catalyzed Allylation.

Trimethyl orthoacetate and ethylene glycol mono-vinyl ether are employed in iridium-catalyzed enantioselective allylation reactions. The method documented enables their convenient use as surrogates for silyl ketene acetals and silyl enol ethers to prepare γ,δ-unsaturated esters and protected aldehydes with excellent enantioselectivity. The utility of this novel method has been demonstrated by its implementation in a formal enantioselective synthesis of the meroterpenoid (+)-conicol.

Synthesis of Allylic Amines by Asymmetric Transfer Hydrogenation of α,β-Unsaturated N-(tert-Butylsulfinyl)imines.

Primary allylic amines with enantiomeric excesses from 97 to >99% were prepared by asymmetric transfer hydrogenation of α,β-unsaturated N-(tert-butylsulfinyl)ketimines followed by removal of the sulfinyl group. The effect caused by different substituents at the C═C bond and at the iminic carbon atom on the chemoselectivity of the reduction was studied. The desired enantiomer of the final allylic amine can be synthesized by choosing the sulfinyl group with the appropriate absolute configuration.