Acid-catalyzed cyclization of anthracenol derivatives to homotriptycenes.
10-Benzyl-9,10-dihydroanthracen-9-ols, having high electron densities in the benzene ring, exhibit in the presence of acid a transannular ring closure to the corresponding homotriptycenes in almost quantitative yields. Since the starting compounds are easily accessible from 9(10H)-anthracenone, this process represents the most facile route to such pentacyclic systems. An electron-releasing methoxy group enables the intramolecular electrophilic substitution in its para position. In the absence of such an activation, a number of alternative processes can occur, namely the acid-catalyzed dehydration to anthracene derivatives with (R not = H) or without (R = H) rearrangement or a disproportionation reaction of the secondary alcohol to the corresponding ketone and hydrocarbon.
Gao
Chunmei
C
LCLC Guangzhou Institute of Chemistry, Chinese Academy of Sciences, Guangzhou 510650, China.
Cao
Derong
D
Xu
Sheyang
S
Meier
Herbert
H
D000143:Acids / Q000737:chemistry*; D000873:Anthracenes / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D011522:Protons; D013696:Temperature; D014867:Water / Q000737:chemistry
D000143:Acids; D000873:Anthracenes; D011522:Protons; D014867:Water