Azolium salts have recently garnered significant attention due to their versatile chemistry, which primarily stems from their flexible structural design. This versatility allows easy customization of their cationic and anionic components, enabling fine-tuning of their physical, chemical, and biological properties. Thus, azolium salts have been intensively investigated for their interactions with biological systems, leading to a wide range of applications, including their use as antitumor agents, antioxidants, antimicrobials, and in bioengineering.1 Additionally, they have emerged as promising precursors for stable N-heterocyclic carbenes (NHCs). Over the past two decades, late-stage structural modifications of azolium salts with alkene, alkyne, (hetero)arene has gained much importance due to their biological as well as tunable electrochemical and photoluminescent properties. Among the various methodologies available, Rh-catalyzed2 annulative π-extension (APEX)3 has become increasingly popular for the functionalization of azolium salts with alkyne (commonly known as annulative alkyne-insertion π-extension (AAIPEX)). Concurrently, there has been a progression in the use of Ru-complexes, transitioning from stoichiometric processes to catalytic approaches over the time.4 In addition to annulative insertion of alkyne, Rh/Ir-catalyzed arylation and heteroarylation have also seen noteworthy developments.5 In this presentation, starting with the C2-functionalization followed by annulative π-extension (APEX) of azolium salts will be discussed in details. Real Money Rummy proposal and some preliminary results as well as future plans will also be presented.
References:
Riduan, S. N.; Zhang, Y. Chem. Soc. Rev. 2013,42, 9055.
(a) C. Dutta, C.; Choudhury, J. RSC Adv. 2018, 8, 27881. (b) Karak, P.; Rana, S. S.; Choudhury, J. Chem. Commun. 2021, 58, 133.
Karak, P.; Dutta, C.; Dutta, T.; Koner, A. L.; Choudhury, J. Chem. Commun. 2019, 55, 6791.
(a) Ma, C.; Ai, C.; Li, Z.; Li, B.; Song, H.; Xu, S.; Wang, B. Organometallics 2014, 33, 5164. (b) Li, R.; Hu, Y.; Liu, R.; Hu, R.; Li, B.; Wang, B. Adv. Synth. Catal. 2015, 357, 3885.
(a) She, Z. J.; Wang, Y.; Wang, D. P.; Zhao, Y. S.; Wang, T. B.; Zheng, X. S.; Yu, Z. X.; Gao, G.; You, J. J. Am. Chem. Soc. 2018, 140, 12566. (b) Liu, Z.; Li, Q.; Yang, C.; Zheng, X.; Wu, D.; Gao G.; Lan, J. Chem. Commun. 2022, 58, 7042.