Cyclophane-type bis-calix[4]arenes: efficient synthesis via quadruple cycloadditive macrocyclization and conformational study

Upper rim-bridged calixarenes

“…52 The conformational studies of these compounds were carried out by solution NMR experiments and X-ray crystallography. 53 When isophthaloyl dichloride 26 was treated with diaminocalix [4]arene 43b in DCM in the presence of pyridine, biscalix [4]arene 100 was obtained in 40% yield. 29b A similar reaction of biphenyl-4,4 0 -disulfonyl chloride 26a provided biscalixarene 101 (38%), which also demonstrates the overall utility of the starting diamine 43b in the synthesis of this type of compounds.…”

“… 52 The conformational studies of these compounds were carried out by solution NMR experiments and X-ray crystallography. 53 …”

Multiple Cycloadditive Macrocyclization: An Efficient Method for Crown Ether-Type Cyclophanes, Bis-Calix[4]arenes and Silamacrocycles

“…Crown-ether type macrocycles, 4 silamacrocycles 20 and bis-calix [4]arenes 21 were synthesized by appropriate combination of bifunctional dipoles and bifunctional dipolarophiles. The ring size of the resulting macrocycles could be controlled through 1+1 double cycloadditive macrocyclization, 2+1 triple cycloadditive macrocyclization, or 2+2 quadruple cycloadditive macrocyclization.…”

“…2+2 Quadruple Cycloadditive Macrocyclization 4,20,21 In all reactions of divinyl ether (diethylene glycol and triethylene glycol) dipolarophiles with bifunctional dipoles, macrocycles formed via 2+2 quadruple cycloadditions were obtained as major products. Synthesis of the 40membered macrocycle 37 is a representative (Scheme 7) of this type.…”