Cyclononanes

Cyclononane, strain energy of, 114 Cyclooctane, strain energy of, 114 Cyclooctatetraene, bond lengths in, 524... 

It is thus anticipated that compressive stress inhibits while tensile stress promotes chemical processes which necessitate a rehybridization of the carbon atom from the sp3 to the sp2 state, regardless of the reaction mechanism. This tendency has been verified for model ring-compounds during the hydrogen abstraction reactions by ozone and methyl radicals the abstraction rate increases from cyclopropane (c3) to cyclononane (c9), then decreases afterwards in the order anticipated from Es [79]. The following relationship was derived for this type of reactions ... 

Macrocyclic ligands 1,4,7-triazacyclonona-iV-acetate 221 and iV-(2-hydroxybenzyl)-l,4,7-cyclononane 225 have been prepared from l,4,7-triazacyclio[5.2.1.04 10]decane 40 and were subsequently used for the synthesis of a series of mono- and dinuclear complexes of vanadium(rv) and (v) (Scheme 35) <1995ICA(240)217>. 

Cycloheptane, cyclooctane, and cyclononane and other higher cycloalkanes exist in nonplanar conformations. 

The conformations of cyclononane are combinations of chair and twist-boat forms as follows ... 

Catalytic methods are suitable for nitrene transfer," and many of those found to be effective for carbene transfer are also effective for these reactions. However, 5- to 10-times more catalyst is commonly required to take these reactions to completion, and catalysts that are sluggish in metal carbene reactions are unreactive in nitrene transfer reactions. An exception is the copper(ll) complex of a 1,4,7-triaza-cyclononane for which aziridination of styrene occurred in high yield, even with 0.5 mol% of catalyst. Both addition and insertion reactions have been developed. 

Bicyclo[5.2.0]nonane-l,7-diol was oxidized by potassium periodate in water at room temperature to yield cyclononane-1,4-dione (6). 56... 

SAMPLE SOLUTION (a) The molecule has a tert-butyl group bonded to a nine-membered cycloalkane. It is tert-butylcyclononane. Alternatively, the tert-butyl group could be named systematically as a 1,1-dimethylethyl group, and the compound would then be named (1,1-dimethylethyl)cyclononane. (Parentheses are used when necessary to avoid ambiguity. In this case the parentheses alert the reader that the locants 1,1 refer to substituents on the alkyl group and not to ring positions.) ... 

Cyclononane prefers a twist boat-chair (TBC) conformation (see references cited in [110]), with two classes of CH2 groups differing in symmetry ( and ). At room temperature, a rapid inversion between two enantiomeric TBC forms probably occurs, involving an intermediate boat-chair form An averaged spectrum having one signal as in Fig. 3.10(e) is observed (Fig. 3.12) [110]. At very low temperature, this inversion is frozen,... 

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