Cyclophanes naphthalenophanes

Details of the yields of cyclophanes, naphthalenophanes, and phenanthrenophanes are summarized in Table 19.2. All phanes possess more than two cyclobutane rings, although they are described simply as [2.2]- and [2n]phanes in this chapter. ... 

The yields of cyclophanes, naphthalenophanes, and phenanthrenophanes synthesized by the intramolecular photocycHzation are summarized in Table 19.4. Again, although all the phanes have at least one cyclobutane ring, they are described here as [2.n] phanes for simplicity. 

The inherent plane of chirality in the metal carbene-modified cyclophane 45 was also tested in the benzannulation reaction as a source for stereoselectivity [48]. The racemic pentacarbonyl(4-[2.2]metacyclophanyl(methoxy)carbene)-chromium 45 reacts with 3,3-dimethyl-1-butyne to give a single diastereomer of naphthalenophane complex 46 in 50% yield the sterically less demanding 3-hexyne affords a 2 1 mixture of two diastereomers (Scheme 30). These moderate diastereomeric ratios indicate that [2.2]metacyclophanes do not serve as efficient chiral tools in the benzannulation reaction. 

EM-values for the formation of cyclophane and naphthalenophane diethers by intramolecular Williamson reaction (51a) in 99% Me2SO at 25°C ... 

The aryl groups of the styryl systems need not be unsubstituted, as has been illustrated before for the cyclizations encountered in the synthesis of naphthalenophanes from 120. Indeed cyclization to afford a cyclobutane derivative where methoxy groups are on the adjacent ring position to the vinyl moieties has also been studied. The irradiation of 138 affords the m-cyclophanes 139 and 14065. Further study has sought to evaluate the steric effect of o-methoxy groups in such molecules66. 

Strong additional support for the assignment of the metapara-cyclophane structure 129 was obtained from dynamic NMR studies The temperature dependence of the proton resonance of this compound is analogous to that of the parent [2.2]metaparacyclophane 3>. The multiplets observed for the protons of the p-phenyl nucleus gradually broaden with increasing temperature, disappear completely at 150 °C, and reappear at 180 °C as a midway peak. The isomer of 129, the 13-methoxy[2]paracyclo[2](l,4)naphthalenophane (132), formation of which by the mechanism outlined above seems equally feasible, does not appear to occur. 

A variety of chiral [m.n]cyclophanes has been described, including [2.2](2,6> naphthalenophane (27) 49-50> and the corresponding diene 49), or [2.2](2,5)pyridino-phanes (28)51). In both cases (27, 28) achiral and chiral isomers (a, b) were isolated and their structures assigned mainly by H-nmr spectroscopy. The chiral structure... 

In 1987, Nishimura, one of the authors, and his co-workers discovered that the [2 -t- 2] photocycloaddition of styrene derivatives proceeds smoothly, when pertinent conditions are carefully chosen. By this method, many cyclophanes including orthocyclophanes, metacyclophanes, paracyclophanes, (4,4 )-biphenylophanes, (1,4)-, (1,5)-, and (2,6)naphthalenophanes, (1,6)- and... 

One of the advantages of this procedure over conventional synthetic methods of azacyclophanes (cyclic amide formation) resides in its brevity and simplicity. In addition, the results obtained reveal this procedure to be an efficient diaza[3.3]cyclophane synthetic method, and an acceptable approach for the synthesis of triazaC3.3.3]cyclophanes and tetraaza[3.3.3.3]cyclophanes as host molecules of inclusion compounds. This synthetic method has been successfully applied to other cyclophane systems, such as 2,ll-diaza[3.3](2,6)-, 2,11,20-triaza[3.3.3](2,6)- and 2,11,20,29-tetraaza[3.3.3.3](2,6)pyridinophane, syn- and anti-2,13-diazaC3.3](1,4)naphthalenophane, 2,13,24-triaza[3.3.3](1,4)- and 2,13,24,35-tetraaza[3.3.3.3](l,4)naphthalenophane. 

Cyclophanes and calixarenes The McMurry reaction has recently found new applications in the synthesis of o-, m-, and p-cyclophane derivatives, which attract much attention in supramolecular chemistry (Figure 6.16). The naphthalenophane 83 exists exclusively in the anti conformation [112]. The extended ring system of compound 84 (R = CeHis) represents a discotic mesogen [113]. In many cases, as for 85 [114] and 86 [115], these compounds are formed together with the products resulting from successive inter- and intracyclization reactions (Section 6.2.3) [114— 119]. 

The photochemical method has been successfully carried out in solution to make cyclophanes," biphe-nylophanes," cyclonaphthalenophanes," naphthalenophanes," " binaphthylophanes, phenan-threnophanes, - biphenylophenanthrenophane, thiophenophanes, and carbazolophanes. Although the cycloaddition approach is quite general, some Hmitations exist as a result of strain and other competitive photoprocesses. °... 

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