Phenylacetylene macrocycles, synthesis

Henze, O., Lentz, D., Schafer, A., Franke, P., and Schluter, A. D. (2002) Phenylacetylene macrocycles with two opposing bipyridine donor sites synthesis, X-ray structure determinations, and Ru complexation, Chem. Eur. J. 8, 357-365 and references therein, (b) Henze, O., Ph.D. Thesis, FU Berlin, Germany, 2000, http //www.diss.fu-berlin.de/2000/47/. 

Tsuji proved the usefulness of this building block in the synthesis of less strained phenylacetylene macrocycles [29, 33]. Sonogashira alkynylation, Glaser-Ellington... 

Discotic liquid crystals of phenylacetylene macrocycles 29 were first reported by Zhang and Moore in 1994 [136]. Their synthesis involves the stepwise build-up of phenylacetylene hexamers [137] followed by a macrocyclization step [138]. The key reactions of the synthesis (Scheme 33) are the palladium-catalysed coupling of aryl iodides and acetylenes, and the selective deprotection steps allowing the ends of the growing oligomer to be distinguished. The synthesis shown is just one of the many possible sequences that can be used to prepare the macrocycles. The mesophase behaviour of the discotic derivatives prepared to date is shown in Table 35 [136]. In some ways... 

Scheme 33. Synthesis of phenylacetylene macrocycles. Reagents (a) K2C03/Me0H (b) Pd(0) (c) MeI/110 C.

Scheme 6.3 Moore and coworkers repetitive synthesis of linear phenylacetylene sequences capable of undergoing high-yield macrocyclizations.

The pioneering dye rotaxane synthesis, reported by Anderson and coworkers in 1996, utilized Glaser coupling under aqueous conditions in the presence of a water soluble cyclophane macrocycle to produce a mixture of [2] and [3]rotaxanes with a conjugated phenylacetylene fiuorophore as the axle component (Figure 11.8). The purpose of the encapsulation was to insulate the conjugated tr-system from quenching processes and both rotaxanes were found to be six fold more fluorescent. 

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