Palladium-Mediated Strategies for Functionalizing the Dihydroazulene Photoswitch: Paving the Way for Its Exploitation in Molecular Electronics

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• 作者：Martyn Jevric ; S酶ren Lindb忙k Broman ; Mogens Br酶ndsted Nielsen
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：May 3, 2013
• 年：2013
• 卷：78
• 期：9
• 页码：4348-4356
• 全文大小：380K
• 年卷期：v.78,no.9(May 3, 2013)
• ISSN：1520-6904

文摘

The dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch has attracted interest as a molecular switch for advanced materials and molecular electronics. We report here two synthetic approaches using palladium catalysis for synthesizing dihydroazulene (DHA) photoswitches with thioacetate anchoring groups intended for molecular electronics applications. The first methodology involves a Suzuki coupling using tert-butyl thioether protecting groups. Conversion to the thioacetate using boron tribromide/acetyl chloride results in the formation of the product as a mixture of regioisomers mediated by a ring-opening reaction. The second approach circumvents isomerization by the synthesis of stannanes as intermediates and their use in a Stille coupling. Although fully unsaturated azulenes are formed as byproducts during the synthesis of the DHA stannanes, this approach allowed the regioselective incorporation of the thioacetate anchoring group in either one of the two ends (positions 2 or 7) or at both.