Open Access
CC BY 4.0 · SynOpen 2025; 09(03): 161-173
DOI: 10.1055/s-0040-1720167
graphical review

Vicarious Nucleophilic Substitution of Hydrogen: An Excellent Tool for Porphyrin Functionalization

Stanisław Ostrowski
,
Agnieszka Mikus


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Abstract

This graphical review addresses the functionalization of porphyrin derivatives. Simple porphyrin modifications (by introduction of an electron-withdrawing group, e.g., NO2, CO-R, into parent porphyrin system or complexation of the core ring with a highly electronegative unit, e.g., SnCl2) afford valuable intermediates in this area of chemistry. They are useful materials for further transformations, as such modifications increase the electrophilic character, thus allowing a broad spectrum of subsequent reactions. Such reactions are often utilized in the first steps of designed syntheses, leading to attractive and useful target porphyrin-like compounds featuring a high degree of complexity. In this regard, the vicarious nucleophilic substitution of hydrogen (VNS) has become one of the methods of choice. Specifically, it involves addition of a carbanion, bearing a leaving group X at the reactive center, to an electrophilic arene at positions occupied by hydrogen to form a σH-adduct. Subsequent base-induced β-elimination of HX then gives the product of nucleophilic substitution of hydrogen. This approach enables the synthesis of numerous porphyrins bearing up to ten new substituents on the meso-aryl rings (attached to positions 5, 10, 15, and 20) and up to six substituents at the β-positions. This graphical review is the first comprehensive account concerning VNS reaction in porphyrins.



Publikationsverlauf

Eingereicht: 20. November 2024

Angenommen nach Revision: 11. Februar 2025

Artikel online veröffentlicht:
29. Juli 2025

© 2025. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by/4.0/)

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