Palladium-catalyzed regio- and stereoselective access to allyl ureas/carbamates: facile synthesis of imidazolidinones and oxazepinones

Palladium-catalyzed (Z)-selective allylation of phosphine oxides with vinylethylene carbonates to construct phosphorus allyl alcohols

Allylphosphine oxide compounds are important building blocks with broad applications in organic synthesis and pharmaceutical science. Herein, we report an unprecedented palladium-catalyzed allylation of phosphine oxides with vinylethylene carbonates, producing various phosphorus allyl alcohols in excellent yields with high Z-selectivity. In addition, gram-scale synthesis and further functional group transformations demonstrate the practical utility of this synthetic method.

Highly diastereo- and enantioselective synthesis of multisubstituted allylic amino acid derivatives by allylic alkylation of a chiral glycine-based nickel complex and vinylethylene carbonates

The asymmetric synthesis of multisubstituted allylic amino acid derivatives was accomplished by the allylic alkylation of a chiral glycine-based nickel complex with vinylethylene carbonates. High enantioselectivities and diastereoselectivities were obtained under mild reaction conditions. The gram-scale synthesis was carried out with a good yield and high enantioselectivity, indicating that the method is a highly efficient route to chiral multisubstituted allylic amino acid derivatives.

Factors Governing Reactivity and Selectivity in Hydrogen Atom Transfer from C(sp3)-H Bonds of Nitrogen-Containing Heterocycles to the Cumyloxyl Radical

A kinetic study of the hydrogen atom transfer (HAT) reactions from nitrogen-containing heterocycles (secondary and tertiary lactams, 2-imidazolidinones, 2-oxazolidinones, and succinimides) to the cumyloxyl radical has been carried out employing laser flash photolysis with ns time resolution. HAT occurs from the C–H bonds that are α to nitrogen, activated by hyperconjugative overlap with the N–C=O π system. In the lactam series, the second-order HAT rate constant (k_H) was observed to decrease by a factor of ∼4 going from the five- and six-membered ring derivatives to the eight-membered ones, a behavior that was rationalized on the basis of a reduced extent of hyperconjugative activation associated to the greater flexibility of the larger rings compared to the smaller ones. In the five-membered-ring substrate series, the k_H values were observed to increase by >3 orders of magnitude on going from succinimide to 2-imidazolidinones, a behavior that was explained in terms of the divergent contribution of hyperconjugative activation and deactivating electronic effects determined by ring functionalities. The results are discussed in the framework of the development of HAT-based C–H bond functionalization procedures.

The Highly Regioselective Synthesis of Novel Imidazolidin-2-Ones via the Intramolecular Cyclization/Electrophilic Substitution of Urea Derivatives and the Evaluation of Their Anticancer Activity

A series of novel 4-(het)arylimidazoldin-2-ones were obtained by the acid-catalyzed reaction of (2,2-diethoxyethyl)ureas with aromatic and heterocyclic C-nucleophiles. The proposed approach to substituted imidazolidinones benefits from excellent regioselectivity, readily available starting materials and a simple procedure. The regioselectivity of the reaction was rationalized by quantum chemistry calculations and control experiments. The anti-cancer activity of the obtained compounds was tested in vitro.