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. 2023 Jul 28;28(15):5704.
doi: 10.3390/molecules28155704.

Photochemical Uncaging of Aldehydes and Ketones via Photocyclization/Fragmentation Cascades of Enyne Alcohols: An Unusual Application for a Cycloaromatization Process

Adam Campbell  1 , Nikolas R Dos Santos  1 , Igor Alabugin  1
Affiliations

Photochemical Uncaging of Aldehydes and Ketones via Photocyclization/Fragmentation Cascades of Enyne Alcohols: An Unusual Application for a Cycloaromatization Process

Adam Campbell et al. Molecules. .

Abstract

We utilized a cycloaromatization reaction driven by relief of excited state antiaromaticity to photouncage aldehydes and ketones. We developed several synthetic routes towards the synthesis of photocaged carbonyls as allylically substituted 3-(2-(arylethynyl)phenyl)prop-2-en-1-ols. A library of photocaged aryl aldehydes and ketones containing donors and acceptors, as well as several photocaged fragrance aldehydes and the steroid 5α-cholestan- 3 -one, were synthesized and demonstrated photouncaging in good to excellent yields.

Keywords: aldehyde synthesis; cycloaromatization; ketone synthesis; photoremovable protecting groups; photouncaging.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
General description of how photocages work.
Scheme 1
Scheme 1
Selected Photocages.
Scheme 2
Scheme 2
Photouncaging Mechanism Initiated by C1–C5 Cycloaromatization.
Scheme 3
Scheme 3
Previous Sonogashira Route to Enynols.
Scheme 4
Scheme 4
General Retrosynthetic Routes to Enynols.
Scheme 5
Scheme 5
Suzuki Route Towards Substituted Enynols.
Scheme 6
Scheme 6
Vinyl Lithium Route Towards Substituted Enynols.
Scheme 7
Scheme 7
Scope of The Vinyl Lithium-Mediated Approach to Photocaged Carbonyls.
Scheme 8
Scheme 8
DIBAL-H Route Towards Substituted Enynols.
Figure 2
Figure 2
1H NMR of the reaction mixture for the photochemical uncaging of p-nitrobenzaldehyde.
Scheme 9
Scheme 9
Caging and photouncaging of 5-α-cholesten-3-one.
See this image and copyright information in PMC

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