Compound 1, a double p-tert-butylcalix[4]arene with direct para-para linkage, was obtained by FeCl3-mediated oxidative coupling of 5,11,17-tri-p-tert-butyl-26,27,28-tribenzoyloxycalix[4]arene-25-ol (4) followed by alkaline hydrolysis. With respect to the de-tert-butylated counterpart 1a, a different reactivity of 1 was observed in the NaH-promoted propylation, which gave octapropyl double-cone atropisomer 6 with higher stereoselectivity. Under competitive conditions 6 was selectively mononitrated at the biphenyl system, whereas ipso-nitration at t-Bubearing rings was obtained using a larger excess of HNO3.
Synthesis of p-tert-Butyl-5,5' -bicalix[4]arene and Access to 5,5'-Bicalix[4]arenes Functionalized at the Upper Rim
2005
Abstract
Compound 1, a double p-tert-butylcalix[4]arene with direct para-para linkage, was obtained by FeCl3-mediated oxidative coupling of 5,11,17-tri-p-tert-butyl-26,27,28-tribenzoyloxycalix[4]arene-25-ol (4) followed by alkaline hydrolysis. With respect to the de-tert-butylated counterpart 1a, a different reactivity of 1 was observed in the NaH-promoted propylation, which gave octapropyl double-cone atropisomer 6 with higher stereoselectivity. Under competitive conditions 6 was selectively mononitrated at the biphenyl system, whereas ipso-nitration at t-Bubearing rings was obtained using a larger excess of HNO3.File in questo prodotto:
Non ci sono file associati a questo prodotto.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
