Question

tertiary alcohols with two identical alkyl groups attached to the alcohol carbon can be made either from an ester and two moles of Grignard reagent, or from a ketone and one mole of Grignard reaction .Use retrosynthetic analysis to suggest one path of each type to synthesize 3-phenyl-3-pentanol.

Route 1  ----->   ester    (draw here)    +       Grignard  (draw here)

                                                                                                            -----> H3O------> 3-phenol-3pentanol

Route 2 --------> Ketone (draw here)  + Grignard (draw here)

Answer 1

Concepts and reason

The concept used to solve this problem is by using the given reagents, reactants, the desired product will be formed. So, label it exactly in the given boxes to form the exact product.

Formation of alcohol using ester, carbonyl compounds with the Grignard reagent. Here, the final product is 3-phenyl-3-pentanol.

Fundamentals

Reaction of aldehydes or ketones with a Grignard reagent followed by the hydrolysis forms a new alcohol.

Esters forms tertiary alcohol when reacted with two equivalents of Grignard reagent.

Route-1:

Retrosynthesis is as follows:

The synthetic reaction for the route 1 is as follows:

Route-2:

Retrosynthesis is as follows:

The synthetic reaction for the route 2 is as follows:

Ans:

The best compounds that are used for the synthesis of 3-phenyl-3-pentanol are as follows: