6

6.5 S-Nucleophiles

• We expect a cyclic acetal because this reaction uses ethylene glycol.
• There are two carbonyl groups in our starting compound.
• There are two groups, one is a ketone and the other is an ester group.
• We've seen that only ketones are converted into acetals.

• The periodic table has sulfur below oxygen.
• The chemistry of sulfur-based compounds is very similar to that of oxygen-based compounds.

• The transformation of thioacetals will not be observed for acetals.

• Raney nickel has hydrogen atoms that are adsorbed to it.
• The reduction process is beyond the scope of this course.
• This is a synthetic transformation.
• Even if you don't know the mechanism, it's worth remembering.

• One way to achieve this kind of transformation has already been seen.

• In the upcoming section, we will see one more way to achieve this transformation.

• Each method has a different set of conditions.
• The reduction uses acidic conditions.
• The method of desulfurization with Raney nickel uses catalytic acid.
• When it isn't good to subject an entire compound to basic conditions, we will see other times.

• Predict the major product that is expected when each of the following compounds is treated with HSCH CH SH.

• Predict the major product that is expected when each of the following compounds is treated with HSCH CH SH and Raney nickel.