6232-58-2Relevant academic research and scientific papers
Alternative general synthetic routes to [2.2]cyclophanes and [3.2]cyclophanes from [3.3]cyclophane-2,11-diones by photodecarbonylation, and a structural study of [3.2]metacyclophanes
Isaji, Hajime,Yasutake, Mikio,Takemura, Hiroyuki,Sako, Katsuya,Tatemitsu, Hitoshi,Inazu, Takahiko,Shinmyozu, Teruo
, p. 2487 - 2499 (2007/10/03)
Photodecarbonylation of [3.3]cyclophane-2,11-diones, which are readily prepared by TosMIC coupling, affords [2.2]cyclophanes in high yield. This method also provides a general synthetic method for [3.2]cyclophan-2-ones by taking advantage of the fact that this photochemical reaction proceeds in a stepwise manner through [3.2]cyclophan-2-ones. A series of [2.2]cyclophanes, [3.2]cyclophanes, and [3.3]cyclophanes can thus be made available from the common precursor [3.3]cyclophane-2,11-diones. In sharp contrast to the preferred syn geometry of [3.3]metacyclophanes, [3.2] metacyclophanes adopt anti geometries and the aryl ring inversion process is observed by variable-temperature 1H NMR spectroscopy. In the crystalline state, the two aryl rings of anti-[3.2]metacyclophanes are almost parallel in spite of the unsymmetrical bridge length; they overlap only at the C-9 and C-17 positions, and the transannular distances are shorter than the corresponding distances in [3.3]metacyclophane-2,11-dione.
Paracyclophane-10-enes and Paracyclophane-10,27-dienes: A Convenient Synthesis by the McMurry Reaction and Dynamic Stereochemistry
Gruetzmacher, Hans-Friedrich,Neumann, Ekkehard,Ebmeyer, Frank,Albrecht, Karsten,Schelenz, Peter
, p. 2291 - 2298 (2007/10/02)
The 1,3-bis(4-acylphenyl)propanes 2, 3, 9, 12, and 15 were subjected to a cyclization by reductive coupling with low-valent titanium (McMurry reaction). 2 and 3 are converted into the corresponding 10,11-dialkylparacyclophane-10-enes 4 and 5, respect
Carbene Isertion into Metacyclophane-1,10-dione: A Convenient Route to - and -Metacyclophanes
Krois, Daniel,Lehner, Harald
, p. 477 - 481 (2007/10/02)
Ring enlargement of metacyclophane-1,10-dione (1) with diazomethane conveniently affords - and -metacyclophanes.The homologues metacyclophane-1,11- and -2,11-diones (2a and b), thus obtained, were used for the synthesis of metacyclophane-1,10-diene (5) and the parent hydrocarbon metacyclophane (4). Metacyclophane-1,12-, -1,11- and -2,11-diones (6a-c), prepared by regioselective carbene insertion into (2a) and (2b) with diazomethane, served as intermediates in the synthesis of metacyclophane (8).The reactivity of the carbonyl groups of oxometacyclophanes decreases with ring size and thus correlates with ring strain.In contrast to (6a-c), the metacyclophanediones (2a and 2b) form hemiacetals when dissolved in methanol.
