An organic reaction

The dehydration of cyclohexanol can arguably be considered as "redox"; however the term "dehydration" can more accurately describe the situation.


圖片參考：http://imgcld.yimg.com/8/n/HA00075708/o/20131208073058.jpg

Refer to the mechanisms. Under path [1], the chloride ion indeed acts as nucleophile, undergoing an Sn2 substitution. Notice that there'd be inversion of configuration, but I didn't show it here.

However, notice that the carbon interested is a secondary carbon, with a quite bulky ring attached to it. Sn2 may not be favored. Therefore it can follow path [2] to undergo E2 elimination, forming an alkene. A base (chloride ion or pyridine) attacks the hydrogen shown, forming cyclohexene.

(There're some tricky things for the hydrogens -- one of the hydrogen is preferentially removed over another. It's related to the 3D-configuration of a 6-member ring, which's not covered here.)

Formation of hydrocarbon should involve a redox reaction by removal of oxygen from cyclohexanol.

It seems that neither SOCl2 nor pyridine can accept the oxygen under the experimental conditions.

The question is tricky. This should only be nucleophilic substitution. Even 1-phenylethanol gives 1-chloro-1-phenylethane.

I am also interesting in the answer behind.