Skip to ContentGo to accessibility pageKeyboard shortcuts menu
OpenStax Logo
Organic Chemistry

13.9 Uses of 1H NMR Spectroscopy

Organic Chemistry13.9 Uses of 1H NMR Spectroscopy

13.9 • Uses of 1H NMR Spectroscopy

NMR is used to help identify the product of nearly every reaction run in the laboratory. For example, we said in Section 8.5 that hydroboration–oxidation of alkenes occurs with non-Markovnikov regiochemistry to yield the less highly substituted alcohol. With the help of NMR, we can now prove this statement.

Does hydroboration–oxidation of methylenecyclohexane yield cyclohexylmethanol or 1-methylcyclohexanol?

Methylenecyclohexane reacts first with borane and tetrahydrofuran, then hydrogen peroxide and hydroxide to form cyclohexylmethanol or 1-methylcyclohexanol; question mark near structures indicates product is unknown, could be either.

The 1H NMR spectrum of the reaction product is shown in Figure 13.16a. The spectrum shows a two-proton peak at 3.40 δ, indicating that the product has a –CH2– group bonded to an electronegative oxygen atom (–CH2OH). Furthermore, the spectrum shows no large three-proton singlet absorption near 1 δ, where we would expect the signal of a quaternary –CH3 group to appear. (Figure 13.16b) gives the spectrum of 1-methylcyclohexanol, the alternative product.) Thus, it’s clear that cyclohexylmethanol is the reaction product.

The 1 H N M R spectrum of cyclohexylmethanol (peaks at 0, 0.9, 1.2, 1.4, 1.7, 2.8. and 3.4) and 1-methylcyclohexanol (peaks at 0, 1.1, and 1.4).
Figure 13.16 (a) The 1H NMR spectrum of cyclohexylmethanol, the product from hydroboration–oxidation of methylenecyclohexane, and (b) the 1H NMR spectrum of 1-methylcyclohexanol, the possible alternative reaction product.
Problem 13-16
How could you use 1H NMR to determine the regiochemistry of electrophilic addition to alkenes? For example, does addition of HCl to 1-methylcyclohexene yield 1-chloro-1-methylcyclohexane or 1-chloro-2-methylcyclohexane?
Order a print copy

As an Amazon Associate we earn from qualifying purchases.


This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's permission.

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution-NonCommercial-ShareAlike License and you must attribute OpenStax.

Attribution information
  • If you are redistributing all or part of this book in a print format, then you must include on every physical page the following attribution:
    Access for free at
  • If you are redistributing all or part of this book in a digital format, then you must include on every digital page view the following attribution:
    Access for free at
Citation information

© Jan 9, 2024 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.