The thioketal product of a certain reaction is given below. Draw the structure of: 
a) the organic reactant 
+ 
b) the pro ecting group reactant 
 ! 
 

1.Explanation | Common mistakes | Hint for next step

In the above mechanism, the sulfur atom of ethan1 2dithol  acts as nucleophile and carbonyl group of cyclohexane acts as electrophile. In the first step, sulfur attacks at the carbonyl carbon, therefore,bondof carbonyl group breaks and oxygen become negatively charged and due to lone pair donation sulfur become positively charged. Since this reaction is performed in the acidic medium so, negatively charged oxygen abstracts proton from acid. After that water molecule takes the proton from sulfur to form a neutral intermediate. In the next step, hydroxyl group abstract proton and become a good leaving group. Then leaving group removes by the movement of electrons. Finally, another sulfur atom attacks at the carbon to form a cyclic compound.

2.Explanation | Common mistakes

In this reaction, cyclohexanone reacts with ethan1 2 dithol in the presence of an acid to form given thioketal product.

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