Synthese mittlerer und großer Ringe, XVI. Bootförmige Arene — Synthese, Struktur und Eigenschaften von [7]Paracyclophanen und [7](1,4)Naphthalinophanen

Abstract

Eine priiparative Synthese der Titelverbindungen 2, 5, 7 und 11, ausgehend von Cyclononanon, wird beschrieben. Schliisselschritte sind die Uberfiihrung von 5,6,7,8,9,furan in die P,V-Heptanooxepine 1, die sich desoxygenieren lassen. Die NMR-Spektren der neuen Cyclophane werden eingehend diskutiert. Rontgenstrukturanalysen von 5 und 11 liefern Deformationswinkel u zwischen 13.6" und 15.9" fur die bootformigen heptanoiiberbriickten Benzolringe. Heptanouberbriickte Ansaverbindungen stellen in verschiedener Hinsicht interessante Grenzfalle dar: Fur die Oxepine 9 und 15 konnte ein Valenztautomeriegleichgewicht mit den entsprechenden [7]Cyclophanoxiden 10 und 16 sehr wahrscheinlich gemacht werden. Das Bis(acetoxymethyl) [7]paracyclophan 2 c addiert unter milden Bedingungen Chlor. 12 liegt nicht als P-Naphthol, sondern als ,,nicht-enolisiertes" Keton vor. Synthesis of Medium and Large Rings, XVI')Boat-shaped Arenes -Synthesis, Structure, and Properties of ['I]Paracyclophanes and [7]( 1,4)Naphthalinopbanes A preparative synthesis of the compounds 2, 5, 7, and 11 starting from cyclononanone is described. Key steps are the conversion of 5,6,7,8,9,1O-hexahydro-4H-cyclonona[c]furan to the P,j3'-heptanooxepines 1, which can be desoxygenated. The NMR spectra of the new cyclophanes are discussed in detail. The deformation angles 01 of the boat-shaped heptanobridged benzene rings were determined for 5 and 11 by X-ray analysis. Values between 13.6" and 15.9" are found. In several respects heptano-bridged ansa compounds are interesting borderline cases: The oxepines 9 and 15 probably exist in a valence tautomeric equilibrium with the corresponding [7]cyclophane oxides 10 and 16. The bis(acetoxymethyl) [7]paracyclophane 2c still adds chlorine under mild conditions. 12 does not exist as P-naphthol but as "non-enolized" ketone.In den vergangenen Jahren haben wir uns eingehend mit der Synthese, Struktur und Chemie von CnlParacyclophanen beschaftigt ' -' ). Die fur [6]Paracyclophane gefundene Deformation des Benzolringes zu einem Boot mit Abknickwinkeln von 0 VCH Verlagsgesellschaft mbH, D

Chemo‐ and Regioselective Intermolecular Cyclotrimerization of Terminal Alkynes Catalyzed by Cationic Rhodium(I)/Modified BINAP Complexes: Application to One‐Step Synthesis of Paracyclophanes

“…A solution of 1,11-dodecadiyne (9 c) (40.6 mg, 0.25 mmol) and dimethyl acetylenedicarboxylate (4 a; 35.5 mg, 0.25 mmol) in CH 2 Cl 2 (3.0 mL) was then added dropwise to this solution over 1 min, and any substrates remaining in the syringe were rinsed into the reaction mixture with further CH 2 Cl 2 (2.0 mL). The mixture was stirred at room temperature for 1 h. The resulting solution was concentrated and the residue was purified by preparative TLC (hexane/ethyl acetate, 6:1), which furnished [8] Dimethyl [7]paracyclophane-9,10-dicarboxylate (11 a) and dimethyl [7]metacyclophane-9,10-dicarboxylate (10 b) (11 a:10 b = 1:0.8): [27] 15 (m, 1 H) Diethyl [7]paracyclophane-9,10-dicarboxylate (11 b) and diethyl [7]metacyclophane-9,10-dicarboxylate (10 c + .…”

“…The reactions of 9 b with various dialkyl acetylenedicarboxylates 4 a-c were investigated at concentrations of 0.01 m, which revealed that the desired highly strained [7]paracyclophanes were obtained along with [7]metacyclophanes (Table 6, entries 1, 4, and 5). [27] The highest yield of [7]paracyclophane was obtained by the use of 4 a ( Table 6, entry 1).…”

3-Heteroquadricyclanes in organic synthesis

“…The oxaquadricyclane -* oxepine approach makes disubstituted [6]and [7]paracyclophanes 90-92 available in amounts that can be used in further preparations. 33,34 These boat-shaped benzene derivatives represent interesting borderline cases. On one hand, they are typically aromatic benzene derivatives with respect to their spectroscopic properties; on the other hand, they very easily undergo the addition and cycloaddition reactions characteristic of alkenes and alkadienes.33,34…”