SYNTHESIS OF CUPPEDOPHANES AND CAPPEDOPHANES - 2 NEW CLASSES OF CYCLOPHANES WITH MOLECULAR CAVITIES

Short routes to cuppedophanes 1 and cappedophanes 2 are described. Key tetrabromide intermediate 8 is synthesized in two steps and 50% overall yield from 2,6-dichloroiodobenzene, 3 (Scheme I). Treatment of 8 with 2 equiv of a dinucleophile such as o-, m- or p-xylylenedithiol results in bridging across the m-terphenyl moiety to give cuppedophanes 23, 17, and 22, respectively. Conversely 8 could be converted to tetrathiol 11 (two steps, 46%), which functioned as a tetranucleophile with dihalides to form cuppedophanes (i.e., 31 and 33). Preparation of cuppedophane 34, containing an intracavity substituent, is described, via precursor 15 (Scheme II). Treatment of 8 with 1 equiv of tetranucleophile 35 gave cappedophanes 36 (16%) and 37 (1.9%). Sulfur atoms in the linking arms of cuppedophanes and cappedophanes were extruded by oxidation to tetrasulfones followed by flash vacuum pyrolysis, leading to hydrocarbons 39, 40, 41, and 43 as well as tilted cappedophane disulfone 44. Certain aromatic protons in cappedophanes are highly shielded; the highest field aryl proton observed thus far appears in 44 at δ 3.31. © 1990, American Chemical Society. All rights reserved.