Chapter 9, Problem 2LGP

Two compounds with the molecular formula ${\text{C}}_5{\text{H}}_{10}\text{O}$ have the following ${}^1\text{H}$ and ${}^{13}\text{C}$ NMR data. Both compounds have a strong IR absorption band in the 1710-1740 cm^−-1 region. Elucidate the structure of these two compounds and interpret the spectra. Make a sketch of each NMR spectrum.

(a)

$\begin{array}{l}{}^{\text{1}}\text{H NMR: δ 2}\text{.55 }\left(\text{septet, 1H}\right)\text{, 2}\text{.10 }\left(\text{s, 3H}\right)\text{, 1}\text{.05 }\left(\text{d, 6H}\right){}^{\text{13}}\text{C NMR: δ 212}\text{.6, }\\ \text{41}\text{.5, 27}\text{.2, 17}\text{.8}\end{array}$

(b)

$\begin{array}{l}{}^{\text{1}}\text{H NMR: δ 2}\text{.38 }\left(\text{t, 2H}\right)\text{, 2}\text{.10 }\left(\text{s, 3H}\right)\text{, 1}\text{.57 }\left(\text{sextet, 2H}\right)\text{, }\\ \text{0}\text{.88 }\left(\text{t, 3H}\right){}^{\text{13}}\text{C NMR: δ 209}\text{.0, 45}\text{.5, 29}\text{.5, 17}\text{.0, 13}\text{.2}\end{array}$