Premium
Partially Hydrogenated [2.2]Paracyclophanes as Precursors in Polycyclic Hydrocarbon Chemistry
Author(s) -
Savinsky Rainer,
Hopf Henning,
Dix Ina,
Jones Peter G.
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200112)2001:24<4595::aid-ejoc4595>3.0.co;2-d
Subject(s) - chemistry , diiodomethane , tetrahydrofuran , adduct , trifluoroacetic acid , diol , medicinal chemistry , ethylene , organic chemistry , crystal structure , olefin fiber , hydrocarbon , cyclooctatetraene , polycyclic compound , catalysis , molecule , solvent , surface energy
The chemical behavior of the tetrahydro‐ and dihydro[2.2]paracyclophanes, 3 and 4 , respectively, was investigated. In particular, 3 was subjected to carbene addition (methylenation with triethylaluminum/diiodomethane, dichloro‐ and dibromocarbene addition) and epoxidation with m ‐chloroperbenzoic acid. The resulting mono adducts 5a , 5b , and 5d were characterized by spectroscopic methods and by chemical transformations to 6 , 7 , and 10 . Reaction of 3 with dehydrobenzene ( 8 ) furnished the ene‐product 9 . Similarly, the bis adducts 14a−c were formed, each in good to excellent yield, from the bis‐olefin 4 . When 14c was ring‐opened by treatment with trifluoroacetic acid, the chiral diol 16 was produced, which was then oxidized to the diketone 18 and brominated to give the dibromide 19 . When the latter was treated with potassium tert ‐butoxide in tetrahydrofuran, it produced the bridged benzobarrelene 21 , the smallest and most highly strained representative of this class of hydrocarbons. On pyrolysis, 21 underwent a retro‐Diels−Alder reaction to pyracene ( 20 ) and ethylene. The derivatives 14b and 16 , which show polymorphism and crystallized in two macroscopically distinguishable crystal forms 16‐I and 16‐II , together with compounds 19 and 21 were amenable to X‐ray crystal structure analysis. The structural properties of these compounds are discussed in detail.