Annulation of Seven‐Membered Rings to [2.2]Paracyclophane

Abstract

Tropylidenes 16 and 17 were prepared from [2.2]paracyclophane (10). On treatment with the corresponding trityl salts they were converted into tropyliophanes 26a (tetrafluoroborate) and 26b (perchlorate). With acetone, 26a furnished trapping product 27, which underwent a homo-Diels-Alder addition with tetracyanoethylene to afford adduct 29. All

Five-membered ring annelation in [2.2]paracyclophanes by aldol condensation

“…We have reported in the past on numerous cyclophane derivatives bearing condensed four- to seven-membered rings, as shown by the representative examples of 1 (E = CO 2 CH 3 ) [ 2 ], 2 [ 3 ], 3 [ 4 ], and 4 [ 5 ]. Many of these compounds possess interesting structural and spectroscopic properties, and can be used as substrates for novel cyclophanes ( Scheme 1 ).…”

“…For example, 2 has been converted into the corresponding bis-olefin, from which multi-layered ferrocene complexes (“metallocenophanes”) were prepared [ 6 ]. Analogously, from 4 several tropyliophane salts were obtained [ 5 ].…”

Improved Synthesis of Enantiopure 4-Hydroxy[2.2]paracyclophane

“…[2.2]Paracyclophanecarboxaldehyde ( 6 ), which is a key compound in our route, can be obtained by a Rieche formylation of unsubstituted [2.2]paracyclophane ( 1 ) in quantitative yield and used without further purification in the next step . It is known that aromatic phenols can be synthesized through a Dakin oxidation of the corresponding aldehydes.…”