Cyclodecane strain energy

Cyclobutanc, angle strain in. 115-116 conformation of. 115-116 molecular model of, 116 photochemical synthesis of, 1190 strain energy of, 114 torsional strain in, 115-116 Cyclodecane, strain energy of. 114 Cyclodecapentaene, molecular model of, 525, 540... 

Small rings are very highly strained. Strain energy decreases to a minimum at the chair conformation of cyclohexane, increases progressiyely to a peak at cyclodecane, then gradually decreases as the ring becomes larger and more closely resembles a linear alkane in its properties. 

This can be thermodynamically explained in that the ring-strain energy is less suitable for the formation of cyclononane from cyclodecane than the formation of cycloheptane from COA (or cyclohexane from cycloheptane) [144]. Overall, these reactions successfully yielded the ring expansion, ring contraction, but this system suffers from the formation of polymers as major products [145]. 

Rings larger than six-membered are always puckered unless they contain a large number of sp atoms (see the section on strain in medium rings, p. 223). The energy and conformations of the alkane series cycloheptane to cyclodecane... 

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