ISSN:
0009-2940
Keywords:
Hydroxy[n.2]metacyclophanes
;
Pyrolysis
;
trans-tert-Butylation
;
syn- and anti-Conformers
;
Ring inversion
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
syn- and anti-Dimethoxy[n.2]metacyclophanes 9 are obtained by pyrolysis of the corresponding anti-sulfones 8, which are prepared by the reaction of 1,n-bis[3-(chloromethyl)-2-methoxyphenyl]alkanes 6 with Na2S in ethanol under the high dilution conditions, followed by the oxidation of the obtained thiametacyclophanes 7 with m-chloroperbenzoic acid. Demethylation of anti-dimethoxy[n.2]metacyclophanes anti-9 with BBr3 in dichloromethane affords the corresponding anti-dihydroxy[n.2]metacyclophanes anti-10. On the other hand, demethylation of syn-dimethoxy[3.2]-syn- 9b and -[4.2]meta-cyclophane syn-9c gives syn-dihydroxy[n.2]metacyclophanes syn-10b, c, but syn-dimethoxy[5.2]-syn-9d and -[6.2]metacyclophane syn-9e are converted into the corresponding anti-dihydroxy[n.2]metacyclophanes anti-10d, e. AlCl3 · CH3NO2-catalyzed de-tert-butylation of tert-butyl-syn- and -anti-dihydroxy[3.2]- and -[4.2]metacyclophanes syn/anti-10b, c has been carried out in benzene to give the desired metacyclophanes anti-11a-c and syn-11c except syn-dihydroxy-[3.2]metacyclophane syn-11b which is converted into 8,17-epoxy[3.2]metacyclophane 13. The assignment of syn and anti conformations has been confirmed by 1H-NMR analyses and X-ray diffraction studies. The dynamics of the ring inversion and UV spectra are also discussed.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19921251116
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