TY - JOUR
T1 - Structure, Resolution, and Racemization of Decakis(dichloromethyl)biphenyl
AU - Biali, Silvio E.
AU - Kahr, Bart
AU - Mislow, Kurt
AU - Okamoto, Yoshio
AU - Aburatani, Ryo
PY - 1988/3/1
Y1 - 1988/3/1
N2 - Decalds(dichloromethyl)biphenyl (1) was obtained by photochlorination of decamethylbiphenyl. Crystals of the 1:1 THF solvate are monoclinic, space group P21/n, a = 17.296 (5) Å, b = 10.091 (3) Å, c = 21.731 (5) Å, 8 = 96.79 (2)°, Z = 4. The disposition of the dichloromethyl groups on both rings is all-geared, and the molecule has approximate C2 symmetry. The 1H NMR solution spectrum of 1 is consistent with a time-averaged C2 conformation. The molecule assumes a curved shape that is well reproduced by empirical force field calculations. Homo- and heterodirectional relationships between subcycles of the molecular model are discussed. Enantiomers of 1 were separated by HPLC on a column of cellulose tris(3,5-dimethylphenylcarbamate). The biphenyl racemizes with a barrier (ΔG) of 23.7 kcal mol−1; the threshold mechanism for the enantiomerization most likely involves internal rotation of the dichloromethyl groups rather than rotation of the pentakis-(dichloromethyl)phenyl groups about the central biphenyl bond.
AB - Decalds(dichloromethyl)biphenyl (1) was obtained by photochlorination of decamethylbiphenyl. Crystals of the 1:1 THF solvate are monoclinic, space group P21/n, a = 17.296 (5) Å, b = 10.091 (3) Å, c = 21.731 (5) Å, 8 = 96.79 (2)°, Z = 4. The disposition of the dichloromethyl groups on both rings is all-geared, and the molecule has approximate C2 symmetry. The 1H NMR solution spectrum of 1 is consistent with a time-averaged C2 conformation. The molecule assumes a curved shape that is well reproduced by empirical force field calculations. Homo- and heterodirectional relationships between subcycles of the molecular model are discussed. Enantiomers of 1 were separated by HPLC on a column of cellulose tris(3,5-dimethylphenylcarbamate). The biphenyl racemizes with a barrier (ΔG) of 23.7 kcal mol−1; the threshold mechanism for the enantiomerization most likely involves internal rotation of the dichloromethyl groups rather than rotation of the pentakis-(dichloromethyl)phenyl groups about the central biphenyl bond.
UR - http://www.scopus.com/inward/record.url?scp=0001484197&partnerID=8YFLogxK
U2 - 10.1021/ja00214a042
DO - 10.1021/ja00214a042
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AN - SCOPUS:0001484197
SN - 0002-7863
VL - 110
SP - 1917
EP - 1922
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 6
ER -