TY - JOUR
T1 - Regioselective Substitution of Aromatic Rings in Calix[4]arene-tricarbonyIchromium Complexes
AU - Iki, Hideshi
AU - Kikuchi, Taketoshi
AU - Shinkai, Seiji
PY - 1993
Y1 - 1993
N2 - We have developed a new method for the substitution of aromatic rings in calix[4]arenes via lithiation of 25, 26, 27, 28-tetrapropoxycalix[4]arenetricarbonylchromium (l∙Cr(CO)3). Since the Cr(CO)3 unit activates the coordinated benzene ring, functional groups (e. g. methyl, formyl, etc.) can be selectively introduced into the Cr(CO)3 complexed benzene ring of cone-l∙Cr(CO)3 and 1, 3-alternate-l-Cr(CO)3 in the yields of 75-96%. We also studied the reactivity of the 1: 2 complex, 1∙2 Cr(CO)3. In the distal isomer two methyl groups were introduced into the p, p-position in 81% yield whereas in the proximal isomer several methylated products were yielded as a mixture. The substitution reaction occurred selectively at the p-position. The high para selectivity was attributed to the structural characteristics of the complexes. Thus, the present study established the novel method for selective introduction of functional gruops into the upper rim of calix[4 jarenes.
AB - We have developed a new method for the substitution of aromatic rings in calix[4]arenes via lithiation of 25, 26, 27, 28-tetrapropoxycalix[4]arenetricarbonylchromium (l∙Cr(CO)3). Since the Cr(CO)3 unit activates the coordinated benzene ring, functional groups (e. g. methyl, formyl, etc.) can be selectively introduced into the Cr(CO)3 complexed benzene ring of cone-l∙Cr(CO)3 and 1, 3-alternate-l-Cr(CO)3 in the yields of 75-96%. We also studied the reactivity of the 1: 2 complex, 1∙2 Cr(CO)3. In the distal isomer two methyl groups were introduced into the p, p-position in 81% yield whereas in the proximal isomer several methylated products were yielded as a mixture. The substitution reaction occurred selectively at the p-position. The high para selectivity was attributed to the structural characteristics of the complexes. Thus, the present study established the novel method for selective introduction of functional gruops into the upper rim of calix[4 jarenes.
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U2 - 10.1246/nikkashi.1993.1353
DO - 10.1246/nikkashi.1993.1353
M3 - Article
AN - SCOPUS:85000922214
SN - 0369-4577
VL - 1993
SP - 1353
EP - 1358
JO - Nippon Kagaku Kaishi / Chemical Society of Japan - Chemistry and Industrial Chemistry Journal
JF - Nippon Kagaku Kaishi / Chemical Society of Japan - Chemistry and Industrial Chemistry Journal
IS - 12
ER -