PROBLEM 12.28

Question

Question: Explain why only one C=C of geraniol is epoxidized with the Sharpless reagent.

Step-by-Step Solution

Verified

Answer

The Sharpless epoxidation occurs only for allylic alcohols, and in geraniol, only one C=C is a part of the allylic alcohol functionality.

1Sharpless epoxidation

Sharpless epoxidation is the conversion of allylic alcohols to epoxide using the reagents tert-butyl hydroperoxide, (CH₃COOH) a titanium catalyst—usually titanium (IV) isopropoxide, Ti[OCH(CH₃)₂]₄ and diethyl tartrate (DET).

The general reaction scheme is given below:

Sharpless epoxidation using (+)-DET and (-)-DET

2Analysis of the given compound

From the structure of geraniol, the allylic alcohol is labeled below:

Allylic alcohol of geraniol

Thus, only one of the C=C groups would take part in the epoxidation reaction since it is a part of the allylic alcohol functionality

PROBLEM 12.27

PROBLEM 12.29

Other exercises in this chapter

PROBLEM 12.26

Question: Sodium hypochlorite (NaOCl, the oxidant in household bleach) in aqueous CH3COOH is also touted as a “green” oxidizing agent. For example,

View solution

PROBLEM 12.27

Question: Draw the products of each Sharpless epoxidation.a.b.

View solution

PROBLEM 12.29

Question: Draw the products formed when A is treated with each reagent: (a) H2 Pd-C; (b) mCPBA; (c) PCC; (d) CrO3, H2SO4, H2O; (e) Sharpless reagent with (+)-DE

View solution

PROBLEM 12.30

Question: Draw the products formed when the following diene is treated with O3 followed by H3CSCH3 .

View solution