An efficient synthesis of new middle-ring disubstituted pentiptycenes from pentiptycene quinone is reported. One of the substituents is a bromo, iodo, amino, nitro, cyano, or formyl group and the other is a hydroxy or alkoxy group. These disubstituted pentiptycenes are potential building blocks for constructing novel pentiptycene-incorporated systems. 3] [4] [5] [6] [7] One of the purposes for using the iptycene group(s) is to spatially isolate the functional moieties from the surroundings and

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... o create intra-or intermolecular free volumes so that the desired properties (e.g., light-emitting efficiency and ability of free rotation) are enhanced. 4c,5-7 In this context, middle-ring functionalized pentiptycenes are particularly attractive, because pentiptycene is the smallest iptycene member that possesses a "spatially isolated" central phenyl ring. Regarding the polyaromaticity and high molecular symmetry of pentiptycene, the middle-ring derivatization would be more effective from the prefunctionalized precursors, particularly the readily prepared pentiptycene quinone 3, 5,8 rather than from the parent pentiptycene 2. 1 Indeed, two important pentiptycene building blocks, pentiptycene hydroquinone 4 and pentiptycene diacetylene 5, have been derived from 3. 5 However, an attempt to prepare the diiodopentiptycene 6 from 3 by following the method for the conversion of the triptycene quinone 7 to the diiodotriptycene 10 via the intermeiates 8 and 9 (Scheme 1