Pd-Catalyzed Allylic Isocyanation: Nucleophilic N-Terminus Substitution of Ambident Cyanide

Organophosphates as Versatile Substrates in Organic Synthesis

This review summarizes the applications of organophosphates in organic synthesis. After a brief introduction, it discusses cross-coupling reactions, including both transition-metal-catalyzed and transition-metal-free substitution reactions. Subsequently, oxidation and reduction reactions are described. In addition, this review highlights the applications of organophosphates in the synthesis of natural compounds, demonstrating their versatility and importance in modern synthetic chemistry.

Biocatalytic One-Carbon Transfer – A Review

This review provides an overview of different C1 building blocks as substrates of enzymes, or part of their cofactors, and the resulting­ functionalized products. There is an emphasis on the broad range of possibilities of biocatalytic one-carbon extensions with C1 sources of different oxidation states. The identification of uncommon biosynthetic strategies, many of which might serve as templates for synthetic or biotechnological applications, towards one-carbon extensions is supported by recent genomic and metabolomic progress and hence we refer principally to literature spanning from 2014 to 2020.

1 Introduction

2 Methane, Methanol, and Methylamine

3 Glycine

4 Nitromethane

5 SAM and SAM Ylide

6 Other C1 Building Blocks

7 Formaldehyde and Glyoxylate as Formaldehyde Equivalents

8 Cyanide

9 Formic Acid

10 Formyl-CoA and Oxalyl-CoA

11 Carbon Monoxide

12 Carbon Dioxide

13 Conclusions

Palladium-Catalyzed Silylcyanation of Ynamides: Regio- and Stereoselective Access to Tetrasubstituted 3-Silyl-2-Aminoacrylonitriles

The palladium-catalyzed silylcyanation of ynamides is described. This reaction is fully regioselective, delivering tetrasubstituted 2-aminoacrylonitriles derivatives exclusively. Unexpectedly, the nature (aryl or alkyl) of the substituent located at the β-position of the ynamide directly controls the stereoselectivity. The reaction tolerates a number of functional groups and can be considered as the first general access to fully substituted 2-aminoacrylonitriles. Given the singular reactivity observed, a computational study was performed to shed light on the mechanism of this intriguing transformation. Relying on the specific reactivity of the newly installed vinylsilane functionality, the scope of 2-aminoacrylonitriles has been enlarged by postfunctionalization.

Catalytic Metal-Enabled Romance of Isocyanides for Use as “C1N1” Synthons in Cyclization: Beyond Radical Chemistry

Cyclizative reactions have attracted considerable attentions in organic synthesis with regard to the high atom economy and synthetic efficiency towards cyclic architectures. Especially, isocyanide-based cyclizations have proven to be a...

Silyl Cyanopalladate-Catalyzed Friedel–Crafts-Type Cyclization Affording 3-Aryloxindole Derivatives

3-Aryloxindole derivatives were synthesized through a Friedel–Crafts-type cyclization. The reaction was catalyzed by a trimethylsilyl tricyanopalladate complex generated in situ from trimethylsilyl cyanide and Pd(OAc)2. Wide varieties of diethyl phosphates derived from N-arylmandelamides were converted almost quantitatively into oxindoles. When N,N-dibenzylamide was used instead of an anilide substrate, a benzo-fused δ-lactam was obtained. An oxindole product was subjected to substitution reactions to afford 3,3-diaryloxindoles with two different aryl groups.

Divergent Synthesis of Isonitriles and Nitriles by Palladium-Catalyzed Benzylic Substitution with TMSCN

Ligand-controlled palladium-catalyzed divergent synthesis of isonitriles and nitriles from benzylic carbonates and TMSCN has been developed. The BINAP- or DPEphos-ligated palladium catalyst selectively provides the corresponding benzylic isonitriles, whereas their regioisomers, benzylic nitriles, are formed exclusively under phosphine ligand-free conditions. Mechanistic studies reveal that isonitrile is the primary product under both conditions, but it is isomerized into nitrile in the absence of ancillary phosphine ligands.

Nucleophilic Isocyanation

Isonitriles are frequently employed as both substrates for organic transformations and ligands for organometallic chemistry. However, despite the wide application of the isonitriles, their synthesis generally depends on the traditional dehydration of N-formamide. "Nucleophilic isocyanation" using cyanide as an N-nucleophile is another straightforward strategy affording the corresponding isonitriles. This method has been available since the 19th century but is still an immature procedure and is therefore more rarely used. In this review, we summarize the concepts and recent progress in nucleophilic isocyanation, including the relatively rare examples of catalytic isocyanation.

Copper-Catalyzed Tertiary Alkylative Cyanation for the Synthesis of Cyanated Peptide Building Blocks

In this paper, we report efficient cyanation of various peptides containing the α-bromocarbonyl moiety using a Cu-catalyzed radical-based methodology employing zinc cyanide as the cyanide source. Mechanistic studies revealed that in situ formed CuCN was a key intermediate during the catalytic cycle. Our method could be useful for the synthesis of modified peptides containing quaternary carbons.

A convenient reagent for the conversion of aldoximes into nitriles and isonitriles

Described herein is the convenient transformation of aldoximes into nitriles or isonitriles by slightly modifying reaction conditions.

Ag2O-catalysed nucleophilic isocyanation: selective formation of less-stable benzylic isonitriles

Both primary and secondary benzylic isonitriles were exclusively produced by the Ag₂O-catalysed reaction of benzylic phosphates and trimethylsilyl cyanide without formation of the thermodynamically favoured regioisomers, benzylic nitriles.

Mechanistic Study on Allylic Arylation in Water with Linear Polystyrene-Stabilized Pd and PdO Nanoparticles

The catalytic cycle of allylic arylation in water catalyzed by linear polystyrene-stabilized Pd or PdO nanoparticles (PS-PdNPs or PS-PdONPs) was investigated. Stoichiometric stepwise reactions indicated that the reaction did not proceed stepwise on the surface of the catalyst. In the case of the reaction with PS-PdNPs, the leached Pd species is the catalytically active species and the reaction takes place through a similar reaction pathway accepted in the case of a complex catalyst. In contrast, allylic arylation using PS-PdONPs as a catalyst occurs via a Pd(II) catalytic cycle.