There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

As valuable C1 building blocks, isocyanides represent an important class of reactive species and synthons. During the past decades, exhaustive efforts have been devoted to the discovery of highly efficient reactions involving isocyanide on the basis of the development of the Passerini and Ugi reactions. Several types of reactions involving isocyanides have been reported, such as nucleophilic attack, electrophilic addition, imidoylation reactions, and oxidation etc. In this review, recent progress in isocyanide insertion chemistry is presented. Among all isocyanide insertions, two catalytic systems have been developed, that is, Lewis (Bronsted) acid-catalyzed isocyanide insertions and transition-metal-enabled isocyanide insertions, respectively. This review is hence written in the sequence of Lewis (Bronsted) acid-catalyzed isocyanide insertion and transitional metal-enabled isocyanide insertion, where isocyanide insertion into heteroatom–hydrogen bonds, carbon–halogen bonds, carbon–hydrogen bonds, and metal carbenes are summarized.

Recent advances in isocyanide insertion chemistry

Metal-mediated and metal-catalyzed reactions of isocyanides.

Ionic liquids as green and sustainable corrosion inhibitors for metals and alloys: An overview

Effects of electron donating (−CH3 and −OH) and electron withdrawing (−NO2) substituents on the corrosion inhibition efficiency of four glucosamine-based, substituted, pyrimidine-fused heterocycles (CARBs) on mild steel corrosion in 1 M HCl have been investigated using gravimetric, electrochemical, surface morphology (SEM, AFM, and EDX), and computational techniques. Gravimetric studies showed that protection performances of the compounds increase with increase in concentration. Both electron withdrawing (−NO2) and electron donating (−CH3 and −OH) groups were found to enhance the inhibition efficiency, but the effect is more pronounced with electron-donating substituents. The compounds were found to be cathodic-type inhibitors as inferred from the results of potentiodynamic polarization studies. EIS studies suggested that the studied compounds inhibit metallic corrosion by adsorbing on metallic surface. The adsorption of the inhibitor molecules on steel surface was further supported by SEM, AFM, and EDX a...

Adsorption Behavior of Glucosamine-Based, Pyrimidine-Fused Heterocycles as Green Corrosion Inhibitors for Mild Steel: Experimental and Theoretical Studies

Multicomponent reactions: advanced tools for sustainable organic synthesis

O(2) in, H(2)O out: Various diamines and related bisnucleophiles readily undergo oxidative isocyanide insertion with Pd(OAc)(2) (1 mol %) as the catalyst and O(2) as the terminal oxidant to give a diverse array of medicinally relevant N heterocycles. The utility of this highly sustainable method is demonstrated by a formal synthesis of the antihistamines astemizole and norastemizole.

Sustainable Synthesis of Diverse Privileged Heterocycles by Palladium‐Catalyzed Aerobic Oxidative Isocyanide Insertion

Synthesis of polycyclic spiroindolines by highly diastereoselective interrupted Ugi cascade reactions of 3-(2-isocyanoethyl)indoles.

https://pubs.rsc.org/en/Content/ArticlePDF/2017/GC/C6GC02493A

Biocatalytic access to nonracemic γ-oxo esters via stereoselective reduction using ene-reductases

Herein, we describe the versatile application of triphenylmethyl (trityl) isocyanide in multicomponent chemistry. This reagent can be employed as a cyanide source in the Strecker reaction and as convertible isocyanide in the preparation of N-acyl amino acids by Ugi 4CR/detritylation and free imidazo[1,2-a]pyridin-3-amines by a Groebke-Blackburn-Bienayme 3CR condensation/deprotection protocol. The mechanisms of these three classical MCRs intersect at the common N-trityl nitrilium ion intermediate, whose predictable reactivity can be exploited towards chemoselective transformations.

Răzvan C. Cioc

Papers

Multicomponent reactions: advanced tools for sustainable organic synthesis

Sustainable Synthesis of Diverse Privileged Heterocycles by Palladium‐Catalyzed Aerobic Oxidative Isocyanide Insertion

Synthesis of polycyclic spiroindolines by highly diastereoselective interrupted Ugi cascade reactions of 3-(2-isocyanoethyl)indoles.

Biocatalytic access to nonracemic γ-oxo esters via stereoselective reduction using ene-reductases

Trityl Isocyanide as a Mechanistic Probe in Multicomponent Chemistry: Walking the Line between Ugi- and Strecker-type Reactions