Catalytic and asymmetric synthesis of heteroatom-containing cyclic polyarylenes

Cyclic polyarylene is a series of compounds, where the cyclic structure is constructed by a number of phenylene and/or heteroarylene moieties. Cyclic polyarylenes consisting of more than three arylene moieties are non-planar, and introduction of substituent (s) induces axial chirality. We comprehensively studied catalytic and enantioselective synthesis of various cyclic polyphenylenes by consecutive inter- and intramolecular cycloadditions of triynes, where 1,6-diyne and alkyne moieties were tethered by phenylene moiety. We further used this strategy for the construction of cyclic heteroarylenes using thiophene-tethered triynes. Next, we focused on the enantioselective construction of sulfur-containing benzo-fused medium ring systems. For examples, intermolecular cycloaddition of 1,8-diynes tethered by sulfur and two ortho-phenylene moieties with an alkyne gave axially chiral poly-substituted tribenzothiepins possessing a seven-membered ring core. We succeeded in the enantioselective synthesis of seven to eleven-membered benzo-fused compounds by intramolecular reaction of triynes consisting of sulfur-tethered 1,6-diyne and 1, «-diyne moieties (n = 8—11).