Section 18-8 covers the synthesis of aldehydes and ketones using 1,3-dithiane as a masked...

Section 18-8 covers the synthesis of aldehydes and ketones using 1,3-dithiane as a masked carbonyl group (the thioacetal of a carbonyl group). Like (oxygen) acetals, thioacetals hydrolyze in dilute acid. Thioacetais are somewhat more stable however, and mercuric (Hg2+) salts are often added as a specific Lewis acid to promote the hydrolysis.

(a) Show how you would make 2-methyi-1,3-dithiane from 1,3-dithiane.

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(b) Propose a mechanism for the acid-catalyzed hydrolysis of 2-methyl-1,3-dithiane.

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(c) Propose a mechanism for how Hg2+ might assist the hydrolysis.