Repetitive Construction of Macrocyclic Oligophenylenes

Abstract

The "base effect" [3a, b] in MTO-catalyzed olefin epoxidations has already been known for some time and provides an enormous extension of this catalyst's variety of application: a) W.

5,5″-Disubstituted 2,2′:6′,2″-Terpyridines through and for Metal-Mediated Cross-Coupling Chemistry

“…The same experiment was also carried out at a much smaller scale (0.457 g 4 a) and gave 3 a with higher yield (66.1 %). 1 …”

“…After the combined organic phases were dried over MgSO 4 , and evaporated, chromatography on silica gel gave 4.37 g of 1 f (69.9 %) as a colorless oil. 1 …”

“…1 2-Bromo-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (8): BuLi (1.6 m, 69 mL) in hexane was added dropwise to a solution of compound 5 (25 g, 105.5 mmol) in Et 2 O (800 mL), while the temperature was kept at À 78 8C. After stirring at À 78 8C for 6 h, a solution of triisopropyl borate (41.67 g, 221.6 mmol) in Et 2 O (50 mL) was added dropwise.…”

“…We have recently reported on repetitive syntheses of oligophenylene hexagons with up to 24 [1] phenylene rings that make these compounds available at a reasonable quantity/ effort relationship. The main motivation for this research is a) to approach extended honeycomblike, two-dimensional networks for which these shape persistent, geometrically regular molecules may serve as constituents, [2] and b) to apply the developed methodology to the synthesis of shapepersistent macrocycles with integral donor moieties like 2,2':6',2''-terpyridine for subsequent transition metal complexation and supramolecular assembly.…”

Template-Directed Synthesis of Shape-Persistent Macrocyclic Amphiphiles with Convergently Arranged Functionalities

“…Either a proper protective group strategy in which one of two or more equal functionalities is selectively protected is required, [10] or repetitive coupling strategies have to be used. The latter approach has been successfully applied in the preparation of macrocyclic structures based on the phenyl, [11] the phenylethynyl [12] or the phenyldiethynyl backbone [13] by intramolecular cyclization of the appropriate precursor. Contrary to statistical cyclization reactions, [14] structures with a defined arrangement of different components within a ring can be prepared in high yields during the cyclization step.…”