S,N-Heteropentacenes – Syntheses of Electron-Rich Anellated Pentacycles

This review summarizes syntheses of S,N-heteropentacenes, i.e. electron-rich sulfur and nitrogen-embedding pentacycles, and briefly highlights selected applications in molecular electronics. Depending on the anellation mode and the number of incorporated heteroatoms, electron density can be raised by increasing nitrogen incorporation and polarizability is manifested by the sulfur content. In comparison to triacene analogues, the conjugation pathways of S,N-heteropentacenes are increased and the favorable acene-typical crystallization behavior allows for diverse application in organic electronics. Furthermore, substitution patterns allow fine-tuning the electronic properties, extending the π-systems, and supplying structural elements for further application.1 Introduction2 Thiophene-Centered S,N-Heteropentacenes2.1 Dipyrrolo-Fused Thiophenes2.2 Diindolo-Fused Thiophenes3 Pyrrole-Centered S,N-Heteropentacenes3.1 Dithieno-Fused Pyrroles3.2 Bis[1]benzothieno-Fused Pyrrole4 Fused 1,4-Thiazines4.1 Dinaphtho-Fused 1,4-Thiazines4.2 Bis[1]benzothieno-Fused 1,4-Thiazines5 Conclusions and Outlook

Dithienopyrrole-based Organic Electroactive Materials and Their Photovoltaic Aspects

4H-dithieno[3,2-b:2',3'-d]pyrrole has recently become a useful building block in the synthesis of donor-acceptor molecules with practical application in various organic technologies. The DTP molecule itself consists of a pyrrole ring with two fused thiophenes providing an alternative for the related dithieno[3,2-b:2′,3′-d]thiophene. Most notably, the significance of DTP-based low- and high-molecular weight species has increased in recent years since, upon proper processing, they allow to improve the performance of many fields of organic electronics. This review is a trial of a brief report on recent advances in modern DTP chemistry with examples of their applications, mostly in the area of organic photovoltaics. The scope of this manuscript was to present the structure-property relationships that had been found together with the development of DTP-based materials.

Recent Advances in Sulfur-Containing Heterocycle Formation via Direct C–H Sulfuration with Elemental Sulfur

The synthesis of sulfur heterocycles via the construction of C–S bonds has received considerable attention due to their biological value and extensive pharmaceutical application. While diverse sulfurating agents have been developed over the past few decades, in this regard, elemental sulfur, with advantages of low toxicity, odorless nature and chemical stability, has great potential for the construction of diverse sulfur heterocycles through its direct incorporation into the target molecules in a concise way. Direct functionalization of inert C–H bonds can shorten the number of reaction steps and minimize the amount of waste formed. Hence, heteroannulations via direct C–H sulfuration is considered to be an attractive strategy for the synthesis of sulfur heterocycles. In the last few years, a vast array of concise systems have been reported for the synthesis of some valuable sulfur heterocycles such as thiophenes, thienoindoles, thienothiazoles, thiazoles, benzothiazoles, and thiadiazoles through direct C–H sulfuration/annulations with elemental sulfur. These are discussed in detail in this review.1 Introduction2 Thiophenes3 Thienoindoles4 Thienothiazoles5 Other Fused Thiophenes6 Thiazoles7 Benzothiazoles8 Thiadiazoles9 Others10 Summary and Outlook

Pd-Catalyzed intramolecular C–H addition to the cyano-group: construction of functionalized 2,3-fused thiophene scaffolds

An efficient synthesis of 2,3-fused thiophenes was demonstrated through a Pd-catalyzed intramolecular C–H addition of thiophenes bearing cyanohydrin components to nitriles.

Regiospecific alkyl addition of (hetero)arene-fused thiophenes enabled by a visible-light-mediated photocatalytic desulfuration approach

A unique photoredox desulfuration approach enabling the regiospecific alkyl addition of (hetero)arene-fused thiophenes is presented.