TY - JOUR
T1 - Bisacetals of aromatic ring-annelated benzo[a,d]bis{bicyclo[4.4.1]undeca-3,8-diene-11-one}. [3.3] [3.3l]orthocyclophanes with triple-layered benzo/benzo/benzo- and naphtho/benzo/naphtho-system
AU - Mataka, Shuntaro
AU - Mitoma, Yoshiharu
AU - Thiemann, Thies
AU - Sawada, Tsuyoshi
AU - Taniguchi, Masahiko
AU - Kobuchi, Masaru
AU - Tashiro, Masashi
PY - 1997/3/3
Y1 - 1997/3/3
N2 - Tetraesters anti 9a,b and syn-9a,b, which have three aromatic rings, were prepared by the reaction of benzocycloheptenediester 7 with 1,2,4,5-tetrakis(bromomethyl)benzene. Subsequent hydrolysis and pyrolysis gave diketones anti-11a,b and syn-11a,b, which were acetalized to yield bisacetals anti-5a,b and syn-5a,b. X-Ray crystallographic analyses indicate a symmetric (twin-chair)/(twin-chair)- conformation of anti-5a,b, in which two naphtho or benzo rings sandwich one benzene ring. Anti-5a and anti-5b(9b)) are rigid structures. The protons of their central aromatic rings show an up-field shift, due to an anisotropic effect of the facing outer aromatic units. In contrast, syn-5a,b are flexible structures.' The UV-spectra of anti-5a,b show a long wavelength shift, as compared to syn-5a,b, suggesting a through-space interaction among the aromatic rings.
AB - Tetraesters anti 9a,b and syn-9a,b, which have three aromatic rings, were prepared by the reaction of benzocycloheptenediester 7 with 1,2,4,5-tetrakis(bromomethyl)benzene. Subsequent hydrolysis and pyrolysis gave diketones anti-11a,b and syn-11a,b, which were acetalized to yield bisacetals anti-5a,b and syn-5a,b. X-Ray crystallographic analyses indicate a symmetric (twin-chair)/(twin-chair)- conformation of anti-5a,b, in which two naphtho or benzo rings sandwich one benzene ring. Anti-5a and anti-5b(9b)) are rigid structures. The protons of their central aromatic rings show an up-field shift, due to an anisotropic effect of the facing outer aromatic units. In contrast, syn-5a,b are flexible structures.' The UV-spectra of anti-5a,b show a long wavelength shift, as compared to syn-5a,b, suggesting a through-space interaction among the aromatic rings.
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U2 - 10.1016/S0040-4020(97)00042-2
DO - 10.1016/S0040-4020(97)00042-2
M3 - Article
AN - SCOPUS:0031550879
SN - 0040-4020
VL - 53
SP - 3015
EP - 3026
JO - Tetrahedron
JF - Tetrahedron
IS - 9
ER -