High School

We appreciate your visit to Identify the reagents that can be used to achieve each transformation in the following Grignard reactions which require the use of a protecting group. This page offers clear insights and highlights the essential aspects of the topic. Our goal is to provide a helpful and engaging learning experience. Explore the content and find the answers you need!

Identify the reagents that can be used to achieve each transformation in the following Grignard reactions, which require the use of a protecting group.

Answer :

a. The reagents are tert-Butyldimethylsilyl chloride (TBDMSCl), pyridine

Methylmagnesium bromide and Tetra-n-butylammonium fluoride (TBAF)

b. The reagents are Ethylene glycol, acid catalyst, [tex]CH_3CH_2CH_2MgBr[/tex]

and aqueous hydrochloric acid (HCl)

PCC (pyridinium chlorochromate)

a) Converting a diol to a primary alcohol

A common protecting group for alcohols is a tert-butyldimethylsilyl (TBDMS) group and can be introduced using tert-butyldimethylsilyl chloride (TBDMSCl) and pyridine as a base. The TBDMS group is stable under the conditions used for Grignard reactions.

After protecting the diol with a TBDMS group, a Grignard reaction can be performed using methylmagnesium bromide to introduce a methyl group at the desired carbon.

b) Converting a vicinal diol to a ketone

Cyclic protecting groups, such as a cyclic acetal or ketal, are appropriate for protecting vicinal diols (two hydroxyl groups on adjacent carbons) because they can protect both hydroxyls in a single step. Ethylene glycol for instance can be used to form a cyclic ketal.

Thanks for taking the time to read Identify the reagents that can be used to achieve each transformation in the following Grignard reactions which require the use of a protecting group. We hope the insights shared have been valuable and enhanced your understanding of the topic. Don�t hesitate to browse our website for more informative and engaging content!

Rewritten by : Barada