Synthesis of 4-Chalcogeno-1-aza-1,3-butadiene Derivatives by Intramolecular Cyano-Diels鈥揂lder Reaction and Borane-Coordination-Induced Fluorescence Enhancement
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- 作者：Akihiko Ishii ; Yutaro Aoki ; Norio Nakata
- 刊名：Journal of Organic Chemistry
- 出版年：2014
- 出版时间：September 5, 2014
- 年：2014
- 卷：79
- 期：17
- 页码：7951-7960
- 全文大小：473K
- ISSN：1520-6904
文摘
4-Thio-1-aza-1,3-butadiene derivatives 3 incorporating a rigid dibenzobarrelene skeleton were synthesized by the intramolecular cyano-Diels鈥揂lder reaction of 9-anthryl cyanoethenyl sulfides 6. The thermal reaction of 6 afforded an equilibrium mixture of 3 and 6, but the cyclization was effectively promoted by the addition of BF3路Et2O or B(C6F5)3 to yield imine鈥揵orane adducts 8 and 9. The imine鈥揵orane adducts emit intense blue fluorescence both in solution and in the crystalline state. This is in stark contrast to free imines 3, which are weakly fluorescent. Selenium analogue 4 and N-oxide 12 of 3a were synthesized, along with their B(C6F5)3 adducts.