Sterically Demanding Flexible Phosphoric Acids for Constructing Efficient and Multi‐Purpose Asymmetric Organocatalysts

Controlling Stereoselectivity with Noncovalent Interactions in Chiral Phosphoric Acid Organocatalysis

Chiral phosphoric acids (CPAs) have emerged as highly effective Brønsted acid catalysts in an expanding range of asymmetric transformations, often through novel multifunctional substrate activation modes. Versatile and broadly appealing, these catalysts benefit from modular and tunable structures, and compatibility with additives. Given the unique types of noncovalent interactions (NCIs) that can be established between CPAs and various reactants─such as hydrogen bonding, aromatic interactions, and van der Waals forces─it is unsurprising that these catalyst systems have become a promising approach for accessing diverse chiral product outcomes. This review aims to provide an in-depth exploration of the mechanisms by which CPAs impart stereoselectivity, positioning NCIs as the central feature that connects a broad spectrum of catalytic reactions. Spanning literature from 2004 to 2024, it covers nucleophilic additions, radical transformations, and atroposelective bond formations, highlighting the applicability of CPA organocatalysis. Special emphasis is placed on the structural and mechanistic features that govern CPA-substrate interactions, as well as the tools and techniques developed to enhance our understanding of their catalytic behavior. In addition to emphasizing mechanistic details and stereocontrolling elements in individual reactions, we have carefully structured this review to provide a natural progression from these specifics to a broader, class-level perspective. Overall, these findings underscore the critical role of NCIs in CPA catalysis and their significant contributions to advancing asymmetric synthesis.

Metal-free amination of alkenes based on maleimides

A metal-free amination of alkenes based on maleimides has been developed. This method features mild reaction conditions and broad substrate scope, and aminomaleimides with EWGs have been synthesized in up to 99% yield. The gram-scale reaction and successful derivatization of the products further demonstrate the applicability of this methodology.

Selective Synthesis of Z-Michael Acceptors via Hydroalkylation of Conjugated Alkynes

Hydroalkylation of terminal alkynes is a powerful approach to the synthesis of disubstituted alkenes. However, its application is largely unexplored in the synthesis of α,β-unsaturated carbonyls, which are common among synthetic intermediates and biologically active molecules. The thermodynamically less stable Z-isomers of activated alkenes have been particularly challenging to access because of their propensity for isomerization and the paucity of reliable Z-selective hydroalkylation methods. We developed a highly Z-selective silver-catalyzed hydroalkylation of terminal conjugated alkynes using alkyl boranes as coupling partners. The reaction allows access to (Z)-α,β-unsaturated esters, secondary and tertiary alkyl amides, aryl amides, and alkyl and aryl ketones and tolerates a wide range of functional groups. The reaction can be performed successfully in the presence of alkyl and aryl halides, esters, protected alcohols, and amines. The hydroalkylation involves the formation of an alkynylboronate complex followed by a 1,2-metalate shift. This sequence of steps mechanistically constrains the stereochemical outcome, which, together with mild reaction conditions, ensures high Z-selectivity.

The Diversity and Evolution of Chiral Brønsted Acid Structures

The chemical space of chiral Brønsted acid catalysts is defined by quantity and complexity, reflecting the diverse synthetic challenges confronted and the innovative molecular designs introduced. Here, we detail how this successful outcome is a powerful demonstration of the benefits of utilizing both local structure searches and a comprehensive understanding of catalyst performance for effective and efficient exploration of Brønsted acid properties. In this concept article we provide an evolutionary overview of this field by summarizing the approaches to catalyst optimization, the resulting structures, and functions.

Organocatalytic activation of hydrogen peroxide: towards green and sustainable oxidations

The advent of organocatalysis provided an additional option in every researcher's arsenal, towards the development of elegant and sustainable protocols for various organic transformations. Oxidation reactions are considered to be key in organic synthesis since oxygenated functionalities appear in many natural products. Hydrogen peroxide is categorized as a green oxidant, since its only by-product is water, offering novel opportunities for the development of green and sustainable protocols. In this review article, we intend to present recent developments in the field of the organocatalytic activation of hydrogen peroxide, providing useful insight into the applied oxidative protocols. At the same time, we will present some interesting mechanistic studies, providing information on the oxygen transfer processes.

1,3-Diamine-Derived Catalysts: Design, Synthesis, and the Use in Enantioselective Mannich Reactions of Ketones

1,3-Diamine-derived catalysts were designed, synthesized, and used in asymmetric Mannich reactions of ketones. The reactions catalyzed by one of the 1,3-diamine derivatives in the presence of acids afforded the Mannich products with high enantioselectivities under mild conditions. In most cases, bond formation occurred at the less-substituted α-position of the ketone carbonyl group. Our results indicate that the primary and the tertiary amines of the 1,3-diamine derivative cooperatively act for the catalysis.