[structure: see text]. All stereoisomers of a cyclic alkyne containing three helicene units, 1,12-dimethylbenzo[c]phenanthrene, are synthesized using a building block. Isomeric [3 + 3]cycloalkynes aggregate in organic solvents. Vapor pressure osmometry reveals dimer formation of (M,M,M)-[3 + 3]cycloalkynes in chloroform and benzene at concentrations above 2 mM. No higher aggregation is observed. The chirality of helicenes plays an important role in self-aggregation, and diastereomeric (M,P,M)-[3 + 3]cycloalkyne forms a dimer only above 15 mM. Aggregation of racemic (M,M,M)-[3 + 3]cycloalkyne or (M,P,M)-[3 + 3]cycloalkyne is much weaker than that of a single enantiomer.

Optically pure 1,12-dimethylbenzo[c]phenanthrene-5,8dicarboxylic acid 1 is prepared in gram quantities, and a series of macrocycles consisting of the helical chiral unit are synthesized.The helical chirality of polycyclic aromatic compounds is well known in organic chemistry. 1 However, their properties are not well understood compared to those of tetrahedral-and axischirality.2.3 We describe here the preparation of the helically c hiral 1,12-dimethyl benzo [ c] phenanthrene-5,8 -dicarbox y lic acid (M)-(+)-l/(P)-(-)-1 in optically pure form (Fig. 1). A series of macrocycles consisting of this C2 symmetric chiral unit were also synthesized.The synthesis of (k)-l started with a diketone 2 (Scheme l).4 'H NMR (CDC13) spectra of 2 showed two methyl absorptions at 6 1.50 and 2.13. Chiral HPLC separation (Daicel, Chiralcel

The spreading behavior of a new type of chiral compound, namely a series of optically active macrocycloamides ((P)-(-)-1, (P,P)-(+)-2, (P,P,P)-(+)-3, and (P,P,P,P)-(+)-4) consisting of the helical chiral unit 1,12-dimethylbenzo[c]phenanthrene-5,8-dicarboxylate, and dianiline derivatives, on the water surface was investigated by measuring surface pressure (π)-area (A) isotherms, with the aim of producing a new type of chiral Langmuir-Blodgett film. Among the four compounds investigated, (P)-(-)-1 and (P,P)-(+)-2 formed condensed monolayers. Moreover, the monolayer of (P)-(-)-1 could be successively transferred onto solid supports by both downward and upward strokes, yielding Y-type LB films. An optically active LB film based on helical chirality was produced for the first time. The properties of the chiral LB film are discussed.

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Helical chiral 1,12-dimethylbenzo[c]phenanthrene-5,8-dicarboxylic acid was synthesized and resolved in multigram quantities. The absolute configuration was determined by X-ray analysis of the bis(camphorsultamamide) derivative. A series of optically active macrocyclic amides consisting of the chiral unit and a dianiline spacer were synthesized by one-pot procedures, and their structures were compared by spectroscopy and X-ray crystallography. One of the cycloamides exhibited catalytic activity in the asymmetric addition of diethylzinc to aromatic aldehydes. N-Alkylated derivatives were also synthesized, which possessed folded structures distinct from those of the parent cyclic amides.