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Photochemical reactions applied to the synthesis of helicenes and helicene-like compounds

Paper ID Volume ID Publish Year Pages File Format Full-Text
31434 44787 2014 19 PDF Available
Title
Photochemical reactions applied to the synthesis of helicenes and helicene-like compounds
Abstract

•Photocyclization is a selective and versatile method for the preparation of helicenes.•Helicene synthesis with the photolytically supported Vollhardt is reported.•Both reactions are key steps in the synthesis of helicenes containing heterocycles.•The preparation of enantiopure helicenes is reported.

Helicenes are composed of ortho annellated benzene moieties. Similar compounds contain heterocyclic or dihydrobenzene rings or smaller rings such as cyclopentadiene or cyclobutadiene (as part of benzocyclobutene units). The present article resumes photochemical reactions used for the preparation of these compounds. A very important and generally applicable reaction used for the synthesis of helicenes and helicene-like compounds is the photocyclization of stilbene subunits followed by oxidation. This reaction is often highly regioselective. The reaction can be conducted in the way that the formation of the helicene structure is favored. This selectivity is caused by the sum of the free valence numbers in the different positions of the stilbene precursor. Very fascinating structures are obtained with the cobalt catalyzed Vollhardt reaction which is photolytically supported. Helicenes are chiral and different methods of asymmetric synthesis were applied to the preparation of these compounds. A very convenient method is optical resolution using HPLC which is now currently used.

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Keywords
Helicenes; Photocyclization; Vollhardt reaction; Aromatic compounds; Heterocycles; Chirality
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Photochemical reactions applied to the synthesis of helicenes and helicene-like compounds
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology C: Photochemistry Reviews - Volume 19, June 2014, Pages 1–19
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us