TBHP/AIBN-Mediated Synthesis of 2-Amino-thioazoles from Active Methylene Ketones and Thiourea under Metal-free Conditions

Recent advances in the application of β-ketonitriles as multifunctional intermediates in organic chemistry

This review discusses the diverse applications of β-ketonitriles in organic synthesis, highlighting protocols that generate various compounds, including cyclic hydrocarbons, aromatic compounds, heterocycles, spirocycles, and fused heterocycles. These compounds serve as valuable building blocks for biologically active scaffolds like chromenes, quinolines, and natural products. It provides an overview of 69 research articles published from 2014 to 2023, focusing on reactions involving benzoyl acetonitrile derivatives and other β-ketonitriles. The methodologies include cascade, domino, and sequential reactions facilitated by different catalysts, showcasing the versatility of β-ketonitriles in organic chemistry.

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH4I

The electrochemical preparation of 2-aminothiazoles has been achieved by the reaction of active methylene ketones with thioureas assisted by ᴅʟ-alanine using NH₄I as a redox mediator. The electrochemical protocol proceeds in an undivided cell equipped with graphite plate electrodes under constant current conditions. Various active methylene ketones, including β-keto ester, β-keto amide, β-keto nitrile, β-keto sulfone and 1,3-diketones, can be converted to the corresponding 2-aminothiazoles. Mechanistically, the in situ generated α-iodoketone was proposed to be the key active species.

Transition-metal-catalyst-free reaction of amides and acetonitriles: synthesis of β-ketonitriles

The first example of the coupling reaction between amide and acetonitrile for the synthesis of β-ketonitriles was developed. Various amides provide the corresponding β-ketonitriles in good yields.

Azobisisobutyronitrile-Initiated Oxidative C-H Functionalization of Simple Alcohols with Diaryl(arylethynyl)phosphine Oxides: A Metal-Free Approach toward Hydroxymethyl Benzo[b]phosphole Oxides and 6H-Indeno[2,1-b]phosphindole 5-Oxide Derivatives

The first metal-free and facile radical addition/cyclization of simple alcohols with diaryl(arylethynyl)phosphine oxides has been described with azobisisobutyronitrile as a radical initiator, affording an efficient and one-pot procedure to access a new class of hydroxymethyl benzo[b]phosphole oxides and 6H-indeno[2,1-b]phosphindole 5-oxides for potential application in organic materials via sequential C(sp³)-H/C(sp²)-H functionalization. The method employs easily accessible starting materials and is endowed with high regioselectivity and broad functional-group tolerance.