Herein, we describe a method to fine-tune the conductivity of single-molecule wires by employing a combination of chemical composition and geometrical modifications of multiple phenyl side groups as conductance modulators embedded along the main axis of the electronic pathway. We have measured the single-molecule conductivity of a novel series of phenyl-substituted carotenoid wires whose conductivity can be tuned with high precision over an order of magnitude range by modulating both the electron-donating character of the phenyl substituent and its dihedral angle. It is demonstrated that the electronic communication between the phenyl side groups and the molecular wire is maximized when the phenyl groups are twisted closer to the plane of the conjugated molecular wire. These findings can be refined to a general technique for precisely tuning the conductivity of molecular wires.

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Tribenzotropone was efficiently synthesized by a ring-expansion method from readily available phenanthrene-9,10-dione via a ringopened diketone as a key intermediate; the diketone was prepared by nucleophilic addition of allyl and vinyl groups, followed by an oxidative ring-opening reaction with lead(IV) acetate. Ring closure by an intramolecular Diels-Alder reaction and subsequent dehydrogenation produced tribenzotropone in 38% overall yield. Ring closure by a MoritaBaylis-Hillman reaction, on the other hand, produced a dibenzo-fused nonanedione in 22% overall yield.

A regioselective synthetic method with which to access 1,3‐tocopheryl glyceride ethers 2 of diverse carboxylic acids was developed through Bu4NBr‐catalyzed ring‐opening of tocopheryl glycidyl ether 1. Steglich esterification of the 1,3‐tocopheryl acetyl‐glyceride ether 2a with various carboxylic acids, followed by selective deprotection of 3‐acetate by LiEt3BH reduction at –78 °C constitutes a regioselective synthetic method of 1,2‐tocopheryl glyceride ethers 4. An example of the differing self‐assembled behavior of phosphorylcholine derivatives 6c and 7c of 1,3‐ and 1,2‐tocopheryl stearoyl‐glyceride ethers in aqueous solution is also described.

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