Synthesis of 1,4-Cyclohexadiene-Based Acetylenic Macrocycles with Cadiot−Chodkiewicz Coupling. Structure of a Tub-Shaped Tetrameric Container
摘要:
The Cadiot-Chodkiewicz coupling of cis-1,4-diethynyl-1,4-dimethoxycyclohexa-2,5-diene and the corresponding ethynyl bromide gave a mixture of acetyenic macrocycles ranging from dimer to octamer in good isolable yields. The trimeric and tetrameric macrocycles have been structurally characterized by single-crystal X-ray crystallography. In the crystal structure of the trimeric macrocycle a molecule of benzene is sandwiched between a pair of macrocyles. The tetrameric macrocycle exhibited a tub-shaped conformation and encapsulated a molecule of ethyl acetate inside the tub.
Synthesis of Functionalized Benzobarrelenes and Azabenzobarrelenes by Rhodium-catalyzed [2+2+2] Cycloaddition
作者:Yuta Miyauchi、Yu Shibata、Ken Tanaka
DOI:10.1246/cl.150925
日期:2016.1.5
It has been established that a cationic rhodium(I)/H8-BINAP complex catalyzes the [2+2+2] cycloaddition of cyclohexadiene-linked 1,7-diynes with monoynes to produce functionalized benzobarrelenes. ...
The Sonogashira-Hagihara coupling reactions of 2,6-diiodopyridine and cis-3,6-diethynyl-3,6-dimethoxycy-clohexa-1,4-diene or cis-9,10-diethynyl-9,10-dimethoxy-9, 10-dihydroanthracene gave macrocyclic compounds having alternating 2,6-diethynylpyridine and 3,6-dimethoxycyclohexa-1,4-diene segments. Transformation of the C(3)-symmetric 2,6-diethynylpyridine-based cyclo-trimer was efficiently achieved using tin-mediated reductive aromatization under mild conditions.