TY - JOUR
T1 - Synthesis and cation complexation selectivity of bis(syn-proximally) functionalized calix[4]arenes
AU - Brunink, Jos A.J.
AU - Verboom, Willem
AU - Engbersen, Johan F.J.
AU - Reinhoudt, David N.
AU - Harkema, Sybolt
PY - 1992
Y1 - 1992
N2 - A general method has been developed for the preparation of bis(syn‐proximally) functionalized calix[4]arenes (6, 8–10). Starting from p‐tert‐butylcalix[4]arene 1a and calix[4]arene 1b syn‐proximally dialkylated calix[4]arenes 2a and 2b, 4, and 5, respectively, were obtained by treatment with 4.2 equiv of NaH and 2.2 equiv of alkylating reagent in DMF. The syn‐proximal substitution pattern was unequivocally proven by an X‐ray structural determination of 2b. Furthermore the influence of different bases on the functionalization of the free hydroxyl groups of 2b with chloroacetone was studied. Cs2CO3 as the base gave the bis(syn‐proximally) functionalized calix[4]‐arene 6 in the highest yield (82%). Cation complexation studies, with the picrate extraction method, showed that subtle changes in regioselective functionalization influences the selectivity for Na4 considerably.
AB - A general method has been developed for the preparation of bis(syn‐proximally) functionalized calix[4]arenes (6, 8–10). Starting from p‐tert‐butylcalix[4]arene 1a and calix[4]arene 1b syn‐proximally dialkylated calix[4]arenes 2a and 2b, 4, and 5, respectively, were obtained by treatment with 4.2 equiv of NaH and 2.2 equiv of alkylating reagent in DMF. The syn‐proximal substitution pattern was unequivocally proven by an X‐ray structural determination of 2b. Furthermore the influence of different bases on the functionalization of the free hydroxyl groups of 2b with chloroacetone was studied. Cs2CO3 as the base gave the bis(syn‐proximally) functionalized calix[4]‐arene 6 in the highest yield (82%). Cation complexation studies, with the picrate extraction method, showed that subtle changes in regioselective functionalization influences the selectivity for Na4 considerably.
U2 - 10.1002/recl.19921111203
DO - 10.1002/recl.19921111203
M3 - Article
SN - 0165-0513
VL - 111
SP - 511
EP - 516
JO - Recueil des travaux chimiques des Pays-Bas
JF - Recueil des travaux chimiques des Pays-Bas
IS - 12
ER -