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Updated: Sep 15, 2025

Microwave-assisted Intramolecular Dehydrogenative Diels-Alder Reactions for the Synthesis of Functionalized Naphthalenes/Solvatochromic Dyes
Published on: April 1, 2013
Photochemical [2 + 2] cycloadditions of naphthalene acrylic acids: templated and untemplated photoreactivity,
Merve Temel1, Gizem Yildiz1, Kaan Berkay Ceyhan1
1Department of Chemistry, Faculty of Science, Bilkent University Ankara 06800 Turkiye yeturkmen@bilkent.edu.tr.
Abstract:
Selective homo- and heterodimerization reactions of naphthalene acrylic acids have been achieved in a diastereocontrolled manner with the use of 1,8-dihydroxynaphthalene as a covalent template in photochemical [2 + 2] cycloadditions. When the reactions were run in solution, cycloaddition products were obtained in good yields (64-88%), which were subsequently detached from the template via a transesterification reaction affording the symmetrical and unsymmetrical cyclobutane products in 75-91% yields. A careful examination of the crystal structures of diester 6a and cycloadduct 15a along with detailed powder XRD and ATR-IR spectroscopic studies revealed an intriguing case of conformational isomerism in 15a arising from the different possible orientations of its two ester carbonyls. The rotational barriers between the different conformers of 15a were calculated to be within the range of 4.19-7.10 kcal mol-1, indicative of rapid interconversion between these conformers in solution at room temperature.
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