Palladium-catalyzed C-H activation of simple arenes and cascade reaction with nitriles: access to 2,4,5-trisubstituted oxazoles

Efficient Synthesis of Cyanohydrin Esters: P(NMe2)3 Mediated Direct Deoxygenation of Acyl Cyanides with Carboxylic Acids

An efficient synthesis of cyanohydrin esters via a P(NMe2)3 mediated direct deoxygenation process has been exploited, circumventing the release or transformation of the CN─ anion during the reaction. This approach possesses a broad scope and acts as a powerful supplement for the construction of diverse cyanohydrin esters. It offers advantages such as mild conditions, straightforward operations, and excellent scalability, affirming the feasibility and versatility of this approach and highlighting its potential in practical synthesis.

Construction of Functionalized α-Imino Ketones via Pd-Catalyzed C-H Addition to Nitriles/Aerobic Oxidation Sequences

Pd(II)-catalyzed addition of sp2 C-H to nitrile/aerobic oxidation sequences for the preparation of functionalized α-imino ketones is described in which readily available heteroarenes and O-acyl cyanohydrins were employed. Various functionalized targeted molecules can be prepared in good yields with high atom and step economy. Moreover, a broad substrate scope and the ready manipulation and availability of the reaction partners enable this protocol to be appealing to explore the chemical space of the construction of functionalized α-imino ketones with high efficiency.

Catalytic cascade synthesis of cyanohydrin esters via water/O2-induced cyanide transfer from K3Fe(CN)6

The copper-catalyzed α-oxygenation of aryl benzyl ketones is merged with a unique water/O2-induced release of cyanide ions from K3Fe(CN)6 and a benzil-cyanide reaction. This strategy gives expedient access to cyanohydrin esters starting directly from broadly accessible aryl benzyl ketones. The cyanide release strategy was further integrated with a copper catalyzed oxygenation-decarbonylation sequence to produce cyanohydrin esters from 1,3-diketones.

Tf2O-Mediated Direct Synthesis of 4-Sulfenylated Oxazoles from β-Keto Sulfoxides and Nitriles

A general and efficient method for the synthesis of 4-sulfenylated oxazoles is described. Trisubstituted oxazoles are obtained in good to excellent yields from β-keto sulfoxides and nitriles. The mechanistic study suggests that the reaction proceeds via the nucleophilic addition of nitriles to the in situ formed α-carbonyl cation followed by intramolecular cyclization.

Synthesis of Diverse γ-Lactams via Rh-Catalyzed C(sp2)-H Addition to Aliphatic Nitriles

We herein report an unprecedented pathway to access γ-lactams using acetonitrile analogues as coupling partners without oxidants, ligands, and Lewis acids. The reaction undergoes Rh-catalyzed C(sp²)-H addition to carbon-bound nitriles with the aid of an amide traceless auxiliary followed by an annulation sequence, featuring a broad substrate scope, good functional group tolerance, and excellent chemo/stereoselectivity. Scale-up reactions and late-stage derivatizations highlight the potential synthetic utility of this methodology. A plausible mechanism is proposed based on mechanistic investigations.

Palladium-catalyzed direct construction of oxazoline-containing polycyclic scaffolds via tandem addition/cyclization of nitriles and arylboronic acids

An efficient construction of oxazoline-containing polycyclic scaffolds through a Pd-catalyzed addition/cyclization of (hetero)arene tethered O-acyl cyanohydrin units and arylboronic acids is described.

Recent Advances in Transition-Metal-Catalyzed C–H Addition to Nitriles

Transition-metal-catalyzed C–H bond addition to nitriles has emerged as a powerful synthetic approach for the construction of C–C bonds in organic synthesis. Due to the merits of atom- and step-economy, as well the easy availability of the starting materials, these transformations not only deliver acyclic aryl ketone products with nitriles­ as C-building blocks, but can also be utilized for the highly efficient­ assembly of azaheterocyclic skeletons using nitriles as C–N building blocks. This short review summarizes recent progress on transition-metal-catalyzed C–C bond-forming reactions based on C(sp2)–H and C(sp3)–H additions to nitriles.

1 Introduction

2 Palladium-Catalyzed C–H Addition to Nitriles

2.1 Palladium-Catalyzed C–H Addition to Nitriles for the Preparation of Ketone (Imine) Products

2.2 Palladium-Catalyzed C–H Addition to Nitriles for the Preparation of Azaheterocycles

2.3 Palladium-Catalyzed C–H Addition to Nitriles/1,2-Rearangement

3 Other Transition-Metal-Catalyzed C–H Additions to Nitriles

4 Summary and Outlook

Nickel-catalyzed multicomponent reaction of dinitriles and hydrazine hydrochlorides with boronic acids: access to 1,3-diaryl-1H-pyrazol-5-amines and 4,5-dihydropyridazin-3(2H)-ones

Developing efficient methods to accommodate azaheterocycles has been the hotspot field in organic synthesis. Herein, we disclose a facile and expeditious avenue to synthesize 1,3-diaryl-1H-pyrazol-5-amines and 4,5-dihydropyridazin-3(2H)-ones via nickel-catalyzed addition,...

Recent Advances on O-Ethoxycarbonyl and O-Acyl Protected Cyanohydrins

Ethoxycarbonyl cyanohydrins and O-acyl cyanohydrins are examples of O-protected cyanohydrins in which the protecting group presents an electrophilic center, contributing to additional reaction pathways. The first section of this review describes recent advances on the synthesis of O-ethoxycarbonyl and O-acyl protected cyanohydrins. Reactions using KCN or alkyl cyanoformates as the cyanide ion source are described, as well as organic and transition metal catalysis used in their preparation, including asymmetric cyanation. In a second part, transformations, and synthetic applications of O-ethoxycarbonyl/acyl cyanohydrins are presented. A variety of structures has been obtained starting from such protected cyanohydrins and, in particular, the synthesis of oxazoles, 1,4-diketones, 1,3-diketones, 2-vinyl-2-cyclopentenones through various methods are discussed.

Synthesis of Imidazoles and Oxazoles via a Palladium-Catalyzed Decarboxylative Addition/Cyclization Reaction Sequence of Aromatic Carboxylic Acids with Functionalized Aliphatic Nitriles

We herein report an efficient approach for the assembly of multiply substituted imidazoles and oxazoles in a single-step manner. These transformations are based on a decarboxylation addition and annulation of readily accessible aromatic carboxylic acids and aliphatic nitriles and exhibit good functional group compatibility and a high step economy. The reaction is scalable, and as-prepared products could be transformed into practical skeletons. Importantly, the late-stage derivatization of Momelotinib highlights the potential utility of this methodology.

Ni-catalyzed cascade coupling reactions: synthesis and thermally-activated delayed fluorescence characterization of quinazolinone derivatives

A nickel-catalyzed cascade coupling of 2-(2-(arylcarbonyl)-4-oxoquinazolin-3(4H)-yl)acetonitrile and arylboronic acid for the synthesis of pyrazino-fused quinazolinones has been developed. The TADF effect of 3a in the solid-state was investigated.