BackIn the mechanism for acetal hydrolysis shown, the ring oxygen atom was protonated first, the ring was cleaved, and then the methoxy group was lost. The mechanism could also be written to show the methoxy oxygen protonating and cleaving first, followed by ring cleavage. Draw this alternative mechanism.
Provide the major product for the following reaction.
Provide the major product for the following reaction.
Provide the chemical steps necessary for the following synthesis.
Provide the major product for the following reaction dealing with the Grignard reagent.
Show how the following transformations may be accomplished in good yield. You may use any additional reagents that are needed.
(c) benzoic acid → phenyl cyclopentyl ketone
(d) 1-bromohept-2-ene → oct-3-enal
Predict the product and draw the mechanism for the acid-catalyzed pinacol rearrangement of the following diols.
(c)
Pyrrole reacts with excess para-(N,N-dimethylamino)benzaldehyde to form a highly colored compound. Draw the structure of the colored compound.
Geminal diols, or 1,1-diols, are usually unstable, spontaneously losing water to give carbonyl compounds. Therefore, geminal diols are regarded as hydrated forms of ketones and aldehydes. Propose a mechanism for the acid-catalyzed loss of water from propane-2,2-diol to give acetone.
Alcohols combine with ketones and aldehydes to form interesting derivatives, which we will discuss in Chapter 18. The following reactions show the hydrolysis of two such derivatives. Propose mechanisms for these reactions.
(b)
Draw the mechanism for the acid-catalyzed pinacol rearrangement of the following diols.
(b)
Predict the product for the acid-catalyzed pinacol rearrangement of the following diols.
(b)
Draw the mechanism for the acid-catalyzed pinacol rearrangement of the following diols.
(a)
Predict the product for the acid-catalyzed pinacol rearrangement of the following diols.
(a)