Macrocyclic compounds synthesis

Intramolecular allylation offers a useful synthetic method for macrocyclic compounds. An application to the synthesis of humulene (83) by the cycliza-... 

ZINKE ZIEGLER Synthesiso1 Cahxarenes Synthesis of calixarenes (a basket-llke macrocyclic compound)... 

The organization of Part Two is according to structural type. The first section, Chapter Seven, is concerned with the synthesis of macrocyclic compounds. Syntheses of a number of heterocyclic target structures appear in Chapter Eight. Sesquiterpenoids and polycyclic higher isoprenoids are dealt with in Chapters Nine and Ten, respectively. The remainder of Part Two describes syntheses of prostanoids (Chapter Eleven) and biologically active acyclic polyenes including leukotrienes and other eicosanoids (Chapter Twelve). 

The use of macrocyclic compounds of the thiophene series for the preparation of macrocyclic alicyclie ketones has been mentioned earlier. " A new synthesis of exaltone has been carried out using (136) as the starting material. ... 

Rossa, L., Vogtle, F. Synthesis of Medio- and Macrocyclic Compounds by High Dilution Principle Techniques, 113, 1-86 (1983). 

Trost and coworkers137 have reported the polymer-supported palladium catalyzed cyclization of 1, l-bis(phenylsulfonyl)epoxyalkene 235 which gives cycloalkanes 236 and 237 in a 2 1 ratio (equation 143). This method has proven useful for the synthesis of macrocyclic compounds under neutral conditions without using high dilution technique. Temperature and concentrations are critical. The best results are achieved if a reaction mixture of 0.1-0.5 m is added to a preheated (at 65 °C) suspension of the catalyst. 

Calixarenes, which are macrocyclic compounds, are one of the best building blocks to design molecular hosts in supramolecular chemistry [158]. Synthesis of calix[4]arenes, which have been adamantylated, has been reported [105, 109]. In calix[4]arenes, adamantane or its ester/carboxylic acid derivatives were introduced as substituents (Fig. 29). The purpose of this synthesis was to learn how to employ the flexible chemistry of adamantane in order to construct different kinds of molecular hosts. The X-ray structure analysis of p-(l-adamantyl)thiacalix[4]arene [109] demonstrated that it contained four CHCI3 molecules, one of which was located inside the host molecule cavity, and the host molecule assumed the cone-like conformational shape (Fig. 30). 

Ring enlargement of cc-nitrocycloalkanones has been extensively used for the synthesis of macrocyclic compounds, as exemplified in Eq. 5.22.37... 

Biologically important arylamines, various kinds of heterocycles, and macrocyclic compounds have been prepared by using resin-bound nitro halo compounds via SNAr reactions. Such a process is very important for combinatorial synthesis of biologically important compounds. Typical examples are presented in Eqs. 9.13—9.21,22-31... 

Omori, T. Substitution Reactions of Technetium Compounds. 176, 253-274 (1996). Ostrowicky, A., Koepp, E., VOgtle, F. The Vesium Effect Synthesis of Medio- and Macrocyclic Compounds. 161, 37-68 (1991). 

Successful applications of RCM to the formation of almost any ring size 5 have been reported in the literature, including medium-sized and macrocyclic compounds. While the synthesis of 5-, 6- and 7-membered rings is rather general [3] (for representative examples see Table 3) and only few failures have been recorded, unfavorable conformational effects and/or strain in the molecule may render the cyclization of larger rings significantly more delicate. Therefore it is appropriate to discuss the present state of the art in this particular field in some detail. 

Rossa, L. and Vogtle, F Synthesis of medio- and macrocyclic compounds by high dilution principle techniques, Top. Curr. Chem., 113, 1 (1983). 

The Wittig reaction was employed to fuse diene 49 and aldehyde 50, in the final stages of the stereoselective synthesis of epothilone B, a macrocyclic compound with potential antifungal properties (equation 31)49. 

Remarkably, this precatalyst could also be successfully applied in the RCM of several representative diene substrates, allowing the synthesis of essentially all ring sizes greater than four, including mono- and bicyclic compounds, in good to excellent yields, as well as a set of uncommon macrocyclic compounds (representative examples are shown in Scheme 37) [140, 141, 143, 298-300]. 

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