Issue 39, 2020

Annulative π-extension of BODIPYs made easy via gold(i)-catalyzed cycloisomerization


Here we report gold(I)-catalyzed cycloisomerization as a new powerful synthetic tool for the preparation of π-extended BODIPY derivatives. The catalytic system PPhF3AuCl/AgSbF6 enables the synthesis of [b]-[2,1]naphtho-fused-BODIPYs (2a–2c) under mild conditions, in excellent yields and short reaction times. The reaction is totally regioselective to the 6-endo-dig product and for the α-position of the BODIPY, which is both the kinetically and thermodynamically favored pathway, as supported by the free energy profile calculated by means of Density Functional Theory (DFT). Moreover, this methodology also allows the synthesis of two new families of [b]-aryl-fused-BODIPYs, namely, [3,4]phenanthro- (2e and 2f) and [1,2]naphtho-fused (2g) BODIPYs. Their molecular and electronic structures were established by NMR and UV-vis spectroscopies as well as single-crystal X-ray diffraction analysis. As can be noted from the X-ray structures, 2a, 2e and 2g present interesting structural differences at both the molecular and packing level. Interestingly, despite being isomers, the UV/vis spectra of 2a and 2g revealed significant differences in their electronic structures. The origin of this finding was studied by Time-Dependent DFT calculations. Calculated DFT Nuclear Independent Chemical Shift (NICS(0)) values also supported the different electronic structures of 2a and 2g.

Graphical abstract: Annulative π-extension of BODIPYs made easy via gold(i)-catalyzed cycloisomerization

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Article information

Article type
Edge Article
21 Feb 2020
08 Jun 2020
First published
12 Jun 2020
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2020,11, 10778-10785

Annulative π-extension of BODIPYs made easy via gold(I)-catalyzed cycloisomerization

J. Labella, G. Durán-Sampedro, M. V. Martínez-Díaz and T. Torres, Chem. Sci., 2020, 11, 10778 DOI: 10.1039/D0SC01054E

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