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Question 11.3: Methyl 2,2-dimethylpropanoate (CH3)3CCO2CH3 has two peaks i...

Predicting Chemical Shifts in ¹H NMR Spectra

Methyl 2,2-dimethylpropanoate(CH_3)_{3}CCO_{2}CH_3 has two peaks in its ¹H NMR spectrum. What are their approximate chemical shifts?

S t r a t e g y
Identify the types of hydrogens in the molecule, and note whether each is alkyl, vinylic, or next to an electronegative atom. Then predict where each absorbs, using Table 11.3 if necessary.

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The -OCH_3 protons absorb around 3.5 to 4.0 δ because they are on carbon bonded to oxygen. The {(CH_3)_3}C- protons absorb near 1.0 δ because they are typical alkane-like protons.

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