[2.2.2.2](1,2,4,5)Cyclophane Quinhydrone—A Donor-Acceptor Cyclophane with an Extremely Short Transannular Distance

✍ Scribed by Prof. Dr. Heinz A. Staab; Dipl.-Chem. Volker Schwendemann

• Publisher: John Wiley and Sons
• Year: 1978
• Tongue: English
• Weight: 245 KB
• Volume: 17
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.197807561

✦ Synopsis

120.0mmol), and CuI (5.00 g) in nitrobenzene (20ml) is heated under reflux for 3 h. The volatile components are distilled off at 0.2 torr (bath temp. 100°C) and the residue chromatographed on a silica gel column with dichloromethane. The third fraction eluted contains 1.64 g (79 %) of pure (3 a), m. p.

182°C (Ref. ['I: ISOT).

Synthesis of ( 5 ) : A stirred solution of n-BuLi (4.0mmol) in ether (5ml) is treated dropwise within 15min at 25°C with a solution of ( 3 a ) (210mg, 1.0mmol) in 20ml THF. Stirring is continued for a further 30min, whereupon a yellow precipitate separates out. The mixture is cooled to -7O"C, treated with 670mg (5.0mmol) of extremely dry CuC12, and then allowed to warm to room temperature within 12 h. After protolysis with 5 rnl methanol, complexation of the copper salt with lOOml conc. ammonia, and extraction several times with hot chloroform, the dried extract is concentrated by evaporation and the residue chromatographed on a silica gel column with dichloromethane/methanol (100 : 1). Recrystallization of the third fraction from chloroform affords 90 mg (43 %) ( 5 ) as colorless crystals which sublime at 3OO0C/O.02 torr and decompose between 420 and 450°C.