Acid-Catalyzed Oxy-aminomethylation of Styrenes.

We report a strong Brønsted acid-catalyzed three-component oxy-aminomethylation of styrenes with sym-trioxane and sulfonamides or carbamates. This transformation provides a variety of 1,3-oxazinanes in moderate to good yields under mild reaction conditions. The obtained heterocycles can be readily transformed into the corresponding 1,3-amino alcohols, which are useful building blocks for the synthesis of pharmaceutically relevant molecules. Mechanistic studies suggest the intermediacy of an in situ formed 1,3,5-dioxazinane and a subsequent reaction with the olefin.

Cu-Catalyzed Enantioselective Protoboration of 2,3-Disubstituted 1,3-Dienes.

A Cu-catalyzed regio- and enantioselective protoboration of 2,3-disubstituted 1,3-dienes is described. The protocol operates under mild conditions and is applicable to symmetrically and unsymmetrically substituted dienes, providing access to homoallylic boronates in consistently high yield, regioselectivity, and enantiomeric ratio. Preliminary investigations point to a complex mechanism.

Acid promoted radical-chain difunctionalization of styrenes with stabilized radicals and (N,O)-nucleophiles.

A difunctionalization of alkenes through sequential addition of a radical and a nucleophile has been developed, which is suggested to proceed by a radical chain mechanism not requiring a catalyst. An electron transfer step to the oxidant benzoyl peroxide is facilitated by protonation with a strong acid.

Asymmetric transfer hydrogenation of cycloalkyl vinyl ketones to allylic alcohols catalyzed by ruthenium amido complexes.

A chemoselective 1,2-reduction of cycloalkyl vinyl ketones via asymmetric transfer hydrogenation is described. The reduction proceeded smoothly with a chiral diamine ruthenium complex as a catalyst and a HCOOH-NEt3 azeotrope as both a hydrogen source and solvent under mild conditions. A wide range of 1-cycloalkyl chiral allylic alcohols were obtained in good yields and up to 87% ee. It was found that the alkyl group plays an important role in the enantioselectivity.

Transformation of Alkynes into Chiral Alcohols via TfOH-Catalyzed Hydration and Ru-Catalyzed Tandem Asymmetric Hydrogenation.

A novel full atom-economic process for the transformation of alkynes into chiral alcohols by TfOH-catalyzed hydration coupled with Ru-catalyzed tandem asymmetric hydrogenation in TFE under simple conditions has been developed. A range of chiral alcohols was obtained with broad functional group tolerance, good yields, and excellent stereoselectivities.

One-pot synthesis of chiral alcohols from alkynes by CF3SO3H/ruthenium tandem catalysis.

A practical one-pot synthesis of chiral alcohols from readily available alkynes via tandem catalysis by the combination of CF3SO3H and a fluorinated chiral diamine Ru(ii) complex in aqueous CF3CH2OH is described. Very interestingly, the combination of fluorinated catalysts and solvent exhibits a positive fluorine effect on the reactivity and enantioselectivity. A range of chiral alcohols with wide functional group tolerance was obtained in high yield and excellent stereoselectivity under simple and mild conditions.