Amide N-C Bond Activation: A Graphical Overview of Acyl and Decarbonylative Coupling

This Graphical Review provides an overview of amide bond activation achieved by selective oxidative addition of the N-C(O) acyl bond to transition metals and nucleophilic acyl addition, resulting in acyl and decarbonylative coupling together with key mechanistic details pertaining to amide bond distortion underlying this reactivity manifold.

Metal-Free Phosphination and Continued Functionalization of Pyridine: A Theoretical Study

This study investigates the mechanism of metal-free pyridine phosphination with P(OEt)₃, PPh₃, and PAr₂CF₃ using density functional theory calculations. The results show that the reaction mechanism and rate-determining step vary depending on the phosphine and additive used. For example, phosphination of pyridine with P(OEt)₃ occurs in five stages, and ethyl abstraction is the rate-determining step. Meanwhile, 2-Ph-pyridine phosphination with PPh₃ is a four-step reaction with proton abstraction as the rate-limiting step. Energy decomposition analysis of the transition states reveals that steric hindrance in the phosphine molecule plays a key role in the site-selective formation of the phosphonium salt. The mechanism of 2-Ph-pyridine phosphination with PAr₂CF₃ is similar to that with PPh₃, and analyses of the effects of substituents show that electron-withdrawing groups decreased the nucleophilicity of the phosphine, whereas aryl electron-donating groups increased it. Finally, TfO⁻ plays an important role in the C–H fluoroalkylation of pyridine, as it brings weak interactions.

Phosphorylation of Carboxylic Acids and Their Derivatives with P(O)–H Compounds Forming P(O)–C Bonds

Herein, we highlight advances in the phosphorylation of readily available carboxylic acids and their derivatives forming synthetically important P(O)–sp3C, P(O)–sp2C, and P(O)–spC bonds, with an emphasis on the results demonstrated since 2010. This review examines the challenges associated with the use of this strategy for the synthesis of organophosphorus compounds and details advances in the design of catalytic systems that suppress these problems thus resulting in notable progress. Mechanistic details are discussed where available.

1 Introduction

2 Formation of P(O)–sp3C Bonds

3 Formation of P(O)–sp2C Bonds

4 Formation of P(O)–spC Bonds

5 Outlook and Conclusion