Synthetic and structural studies of [6]-, [7]- and [10]metacyclophanes

Hirano, S.; Hara, H.; Hiyama, Tamejiro; Fujita, Shinsaku; Nozaki, Hitosi

doi:10.1016/0040-4020(75)80219-5

Cited by 73 publications

(33 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…While [6] cyclophane (Scheme 1: 1, A = CH 2 CH 2 , X = H) is reasonably stable, 8 [5]metacyclophane (1, A = CH 2 , X = H) slowly polymerizes on standing at room temperature, 9 and [4]metacyclophane (1, A = -) is too unstable to be isolated, so that its intermediacy could only be demonstrated by interception reactions. 10 Correspondingly, the [n]paracyclophanes 2 (n = 8 or 7) are stable under ordinary conditions; [6]paracyclophane is a borderline case; [5]paracyclophane must be kept below À20°C;…”

Section: Reactions Of Small Cyclophanesmentioning

confidence: 99%

Unusual reactivity of highly strained cyclophanes

Bickelhaupt¹,

Wolf²

1998

J. Phys. Org. Chem.

View full text Add to dashboard Cite

An essential feature of the concept of aromaticity has been the stability and lack of reactivity of aromatics relative to that of other unsaturated compounds. Contrary to this general experience, high and unusual reactivity is encountered when simple, monocyclic benzene rings are bent by short bridges into a boat-shaped conformation, as is the case in small [n] paracyclophanes (n 8) and [n]metacyclophanes (n 7). This is illustrated, mostly with examples taken from the authors' own work, for thermal and photochemical behavior and reactions with electrophiles, nucleophiles and dienophiles.

show abstract

Section: Reactions Of Small Cyclophanesmentioning

confidence: 99%

Unusual reactivity of highly strained cyclophanes

Bickelhaupt¹,

Wolf²

1998

J. Phys. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…The synthesis of [6]metacyclophane (2a) was first reported by Hirano et al in 1975. [11] Our approach to small [n]metacyclophanes follows a different strategy, initially developed for the preparation of the more strained lower homologues 1.…”

Section: Synthesismentioning

confidence: 99%

“…In particular, our interest was roused by some seemingly contradictory reports in the literature concerning the DielsϪAlder reactivity of 2. Thus, Hirano et al reported that ''attempted cycloaddition of dienophiles on [6]metacyclophanes failed'', [11] and we found that the 9,12-dichloro derivative 2c did not react with tetracyanoethene at 60°C. [12] On the other hand, the less strained higher wards tetracyanoethene was investigated in order to clarify seemingly contradictory reports in the literature.…”

Section: Introductionmentioning

confidence: 99%

Some Investigations on [6]Metacyclophanes

et al. 2001

View full text Add to dashboard Cite

6]Metacyclophanes 2 with chlorine or fluorine substituents have been synthesized by a novel, convenient version of the base-catalyzed double elimination of hydrogen chloride from the corresponding halopropellanes 7. Conformational analysis by 1 H and 13 C NMR spectroscopy revealed remarkable analogies of certain partial structures of the hexamethylene bridge of 2 with the known exo and endo conformers of [5]metacyclophanes 1. The Diels−Alder reactivity of 2 to-

show abstract

“…The supernatant solution was removed and hydrolyzed; it contained 10% diphenylmagnesium [according to the titration for Mg 2ϩ and OH Ϫ (acid/ Interestingly, the intra-annular aromatic xylylene protons ArЈH are deshielded by 0.4 ppm. This is reminiscent of analogous behavior of aryl protons inside the cavity of small metacyclophanes; [20,21] it has been ascribed to the van der Waals effect caused by steric congestion. [22] As similar changes have also been observed for 6 [9] and 7, [11] these phenomena are indicative of the rotaxane-type threading of a diarylmagnesium into a m-xylylene crown ether cavity.…”

Section: Complexation Of 8 With Diarylmagnesium Compoundsmentioning

confidence: 99%

In Quest of the Double Rotaxane Formation of the Bis(coronand) (1,5),(2,4)‐Durenetetrayl‐bis(18‐crown‐5) with Organomagnesium Compounds

et al. 2003

View full text Add to dashboard Cite

The interaction between the title compound, bis(coronand) 8, and the diarylmagnesium compounds Ph 2 Mg and (ptBuC 6 H 4 ) 2 Mg in diethyl ether leads to the formation of 1:2 complexes (9 and 10, respectively), irrespective of the initial ratio of the components. In [D 8 ]toluene, the three complex types can be discerned by 1 H NMR spectroscopy: double side-on (9a, 10a), side-on/rotaxane (9b, 10b), and, to a very minor extent, double rotaxane (9c, 10c). In the case of 10a and 10b, the temperature dependence showed that rotaxane formation is enthalpically favored at the expense of a more

show abstract

Synthetic and structural studies of [6]-, [7]- and [10]metacyclophanes

Cited by 73 publications

References 59 publications

Unusual reactivity of highly strained cyclophanes

Unusual reactivity of highly strained cyclophanes

Some Investigations on [6]Metacyclophanes

In Quest of the Double Rotaxane Formation of the Bis(coronand) (1,5),(2,4)‐Durenetetrayl‐bis(18‐crown‐5) with Organomagnesium Compounds

Contact Info

Product

Resources

About