Enantiopure silanediols derived from BINOL are an innovative family of stereoselective hydrogen-bond donor (HBD) catalysts. Silanediols incorporated into a BINOL framework are attractive catalysts, as they are readily accessible and highly customizable. Structural modifications of the BINOL backbone affect the reactivity and selectivity of the silanediol catalysts in the additions of silyl ketene acetals to N-acyl isoquinolinium ions. The best results were obtained when the silanediol scaffold was substituted at the 4,4′- and 6,6′-positions. This report includes details regarding the properties of selected BINOL-based silanediol catalysts, including their acidities, binding constants, and X-ray crystal structures.

Dual hydrogen-bond donor (HBD) scaffolds can be strategically designed to enable their optimal performance as catalysts. The deliberate installation of activating groups on HBDs containing conventional functionalities, such as ureas and thioureas, has emerged as one fruitful direction in the identification of catalysts with enhanced activity and improved stereocontrol. Alternatively, new families of HBDs based on structurally unique, inherently more acidic functional groups, such as squaramide and aminopyridinium systems, have proven advantageous over conventional HBD catalysts in select processes. The appropriate incorporation of activating design elements into HBD catalyst frameworks is currently determined empirically and dictated by the specific process under development; each individual reaction benefits from tuning of the HBD catalyst acidity, steric environment, and/or electronic environment. This review presents recent design elements integrated into dual HBD catalyst scaffolds and their influence on HBD catalyst performance.

Phosphoric acid derivatives operate as effective catalysts for the synthesis of glycines in high yield through multicomponent coupling reactions of nitrodiazoesters, anilines, and indoles. This interesting process requires double polarity reversal, or umpolung, of the ester functionality: two nucleophiles undergo addition to the carbon alpha to an ester. Modest control over the absolute stereochemistry of the glycine products is attainable under the influence of chiral BINOL-based phosphoric-acid-derived catalysis.

Nitrimines are employed as powerful reagents for metal-free formal C(sp²)–C(sp²) cross-coupling reactions. The new chemical process is tolerant of a wide array of nitrimine and heterocyclic coupling partners giving rise to the corresponding di- or trisubstituted alkenes, typically in high yield and with high stereoselectivity. This method is ideal for the metal-free construction of heterocycle-containing drug targets, such as phenprocoumon.

The enhanced catalytic activity of difluoroboronate ureas proved to be essential as an acidity amplifier to promote metal-free OH and SH insertion reactions of α-aryldiazoacetates in high yield. This methodology was found to be generally applicable to a broad substrate scope and presents a conceptually new approach for organocatalytic diazo insertion reactions. Mechanistic investigations suggest that the reaction pathway involves a urea-induced protonation of the α-aryldiazoester.

Carbon dioxide is an abundant and renewable C₁ source. However, mild transformations with carbon dioxide at atmospheric pressure are difficult to accomplish. Silanediols have been discovered to operate as effective hydrogen-bond donor organocatalysts for the atom-efficient conversion of epoxides to cyclic carbonates under environmentally friendly conditions. The reaction system is tolerant of a variety of epoxides and the desired cyclic carbonates are isolated in excellent yields.

Nitrimines are employed as powerful reagents for metal-free formal C(sp²)–C(sp²) cross-coupling reactions. The new chemical process is tolerant of a wide array of nitrimine and heterocyclic coupling partners giving rise to the corresponding di- or trisubstituted alkenes, typically in high yield and with high stereoselectivity. This method is ideal for the metal-free construction of heterocycle-containing drug targets, such as phenprocoumon.