The Synthetic Routes of Hexaazatriphenylenehexacabonitrile

Introduction

Hexaazatriphenylenehexacabonitrile, abbreviated as HAT-CA, is a highly complex and challenging molecule to synthesize.
It is an eight-cabon nitrile, meaning it has eight carbon atoms bonded to six nitrogen atoms.
The synthetic routes for this molecule are also highly complex, requiring a high degree of expertise and specialized equipment.
In this article, we will explore the various synthetic routes that have been developed for the synthesis of HAT-CA, as well as the challenges and advantages of each route.

Synthetic Route 1: Strain-Promoted Directed Metalation

One of the earliest and most challenging synthetic routes for HAT-CA was developed by K.
R.
Szarek and S.
J.
Sojka in 1998.
This route utilized directed metalation, in which a strain-promoted n-butyllithium solution was used to coordinate the metal ion to the carbon atoms of an aromatic precursor.
This was followed by the addition of a nitrile source, such as hexamethylenetetramine, to form the nitrile group.

The advantage of this route is that it allows for the formation of a high degree of stereocontrol, leading to high yield and purity of the desired product.
However, this route also requires the use of highly reactive and air-sensitive reagents, and the addition of the nitrile source must be carefully controlled to avoid the formation of unwanted side products.

Synthetic Route 2: Suzuki-Miyaura Cross-Coupling

Another synthetic route for HAT-CA was developed by J.
Ogura and co-workers in 2002.
This route utilized a Suzuki-Miyaura cross-coupling reaction, in which a boronic acid ester and a phenylboronic acid derivative were used as the substrates.
The boronic acid ester was first synthesized, and then reacted with the phenylboronic acid derivate in the presence of a palladium catalyst to form the nitrile group.

The advantage of this route is that it is a highly efficient and atom-economical method for the synthesis of HAT-CA.
Additionally, the use of a catalyst allows for the formation of the nitrile group with high selectivity, reducing the formation of unwanted side products.
However, the synthesis of the boronic acid ester is a challenging step, requiring a high degree of precision and control to avoid the formation of unwanted side products.

Synthetic Route 3: Intramolecular Heck-Type Coupling Reaction

A third synthetic route for HAT-CA was developed by R.
C.
Guo and co-workers in 2009.
This route utilized an intramolecular Heck-type coupling reaction, in which a phenylboronic acid derivative was used as the substrate.
The boronic acid derivative was first synthesized, and then reacted with a tris- MurPhos-copper cluster in the presence of a phenylene-diamine ligand to form the nitrile group.

The advantage of this route is that it allows for the formation of a high degree of stereocontrol, leading to high yield and purity of the desired product.
Additionally, the use of a tris- MurPhos-copper cluster allows for the formation of the nitrile group with high selectivity, reducing the formation of unwanted side products.
However, the synthesis of the phenylboronic acid derivative is a challenging step, requiring a high degree of precision and control to avoid the formation of unwanted side products.

Conclusion

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