Applications of Transition-Metal-Catalyzed Asymmetric Allylic Substitution in Total Synthesis of Natural Products: An Update.

Metal-catalyzed asymmetric allylic substitution (AAS) reaction is one of the most synthetically useful reactions catalyzed by metal complexes for the formation of carbon-carbon and carbon-heteroatom bonds. It comprises the substitution of allylic substrates with a wide range of nucleophiles or SN 2'-type allylic substitution, which results in the formation of the above-mentioned bonds with high levels of enantioselective induction. AAS reaction tolerates a broad range of functional groups, thus has been successfully applied in the asymmetric synthesis of a wide range of optically pure compounds. This reaction has been extensively used in the total synthesis of several complex molecules, especially natural products. In this review, we try to highlight the applications of metal (Pd, Ir, Mo, or Cu)-catalyzed AAS reaction in the total synthesis of the biologically active natural products, as a key step, updating the subject from 2003 till date.

Synthesis of N-heterocycles containing 1,5-disubstituted-1H-tetrazole via post-Ugi-azide reaction.

Ugi-azide four-component reaction (UA-4CR) as development on Ugi four-component reaction (U-4CR) is the condensation reaction involving an aldehyde, an amine, an isocyanide, and an azide source. Nowadays, UA-4CR has been employed for the efficient and facile production of 1,5-disubstituted-1H-tetrazoles (1,5-DS-1H-Ts). Interestingly, the combination of 1,5-DS-1H-Ts with suitable post-transformations in a tandem manner results in the construction of various classes of heterocyclic compounds bearing 1,5-DS-1H-T moiety. This review aims to provide the application of diverse post-Ugi-azide reaction in the preparation of different N-heterocyclic compounds bearing 1,5-DS-1H-T such as substituted and fused 1,5-DS-1H-Ts.

Current progress in asymmetric Biginelli reaction: an update.

The Biginelli reaction, involving a three-component reaction of an aromatic aldehyde, urea and ethyl acetoacetate, has emerged as an extremely useful synthetic tool to organic chemists for the synthesis of 3,4-dihydropyrimidine-2-(1H)-ones and related heterocyclic compounds. In the past decades, the asymmetric variants of this reaction have been at the forefront of investigations in several research groups. In 2013, we highlighted the developments occurred in the asymmetric version of the Biginelli reaction. This review article focuses on the recent developments of asymmetric Biginelli reaction covers the literature going back to 2012.

Microwave-Assisted Synthesis of Quinazolines and Quinazolinones: An Overview.

Microwave irradiation (MWI), as a unique, effective, sustainable, more economic, and greener source of energy compared to conventional heating, is applied in different organic transformations to result in the rapid formation of desired compounds due to thermal/kinetic effects. In this review, we try to underscore the applications of microwave irradiation (MWI) in the synthesis of quinazoline and quinazolinone derivatives that have been achieved and reported on in the last two decades.

Beyond a solvent: triple roles of dimethylformamide in organic chemistry.

N,N-Dimethylformamide (DMF) is frequently used as an aprotic solvent in chemical transformations in laboratories of academia as well as in those of chemical industry. In the present review, we will reveal that DMF is actually something much more than a solvent. It is a unique chemical since, as well as being an effective polar aprotic solvent, it can play three other important roles in organic chemistry. It can be used as a reagent, a catalyst, and a stabilizer.