Cyclodecane, structure

Examine the structure of cyclodecane, a molecule which contains the same number of carbons as decalin, but only has one ring (a model of the most stable conformation is provided). Compare it to cis and trans decalin. Make a plastic model of cyclodecane. Is it flexible or locked What conformational properties of cyclodecane can be anticipated from the properties of decalins What properties cannot be anticipated How do you account for this ... 

The simple cycloalkanes (CH2)n with n = 5 to 12 are the compounds most frequently studied by force field calculations (8, 9, 11, 12,17, 21). This preference results from their simple structure, from the abundant available experimental material (structural (46), thermo-chemical (47) and vibrational spectroscopic (27, 48, 49) data), and from the fact that, apart from bond length deformations, all other strain factors (angle deformations, unfavourable torsion angles, strongly repulsive nonbonded interactions) are important for the calculation of their properties. The cycloalkanes are thus good candidates for testing force fields. For a more detailed discussion we choose cyclodecane, a so-called medium-ring compound. 

When cyclodecane-1,6-dione is treated with sodium carbonate, the product gives a UV spectrum similar to that of 1 -acetyl-2-methylcyclopentene. Propose a structure for the product, and give a mechanism for its formation. 

Skeletal structures of cycloalkanes imply that there is empty space in the middle of the rings. Use SpartanView to look at. space filling models of cyclohexane, cyclodecane, and Qrclooctadecane. Which, if any, rings have empty space ... 

A full structure has been reported for the centrosymmetric hydrated 1,6-diphosphacyclodecane derivative (25), in which the ten-membered ring has the normal cyclodecane conformation. The phenyl groups are in trans-pseudo-axial positions and the structure is completed by hydrogen bonds between the hydrate water and phosphoryl groups from two molecules. 

Fig. 9.4. Left Structure of cyclodecane. The dotted lines show the short H. .. H interactions. Right The cyclodecyl cation intermediate after removal of the tosylate leaving group (see 6)...

Draw flat structures of cyclooctane, cyclodecane, and cyclotri-decane. 

Fragments of chair cyclohexanes are sometimes seen in the structures of mediumsized rings. Cyclodecane is an example, as Figure 5.17 shows. Several destabilizing interactions between carbon-hydrogen bonds should be apparent, especially if you make a model. 

Compare the structure of cyclodecane in an aU-chair conformation with that of fraws-decalin. Explain why aU-chair cyclodecane is highly strained, and yet fraws-decalin is nearly strain free. Make models. 

Some years ago, when PEF400 was new, it was applied to cyclodecane. Five conformations were selected. Three of them have been found in crystal structures Nos. 1, 2 and 4 in Table 10-3 No. 3... 

Heinrich, M.R. and Steglich, W. (2001) Synthesis of (—)-(3S)-l-(3-aminopropyl)-3-methylaza-cyclodecane, the structure proposed for the marine alkaloid halidorensin. Tetrahedron Lett., 42, 3287-3289. 

---