Chemical Shift Assignments: δ 0.77 (d, 6H, J = 7.2 Hz), 2.10 (septuplet of doublets, 2H, J = 7.2 Hz, 1.2 Hz), 9.29 (d, 1H, J = 1.2 Hz)

The doublet at δ 0.77 represents two equivalent methyl groups coupled by 7.2 Hz to a single vicinal hydrogen. The latter hydrogen must be coupled by 7.2 Hz to the hydrogen at δ 2.10, which accounts for the septuplet. This hydrogen is also coupled by 1.2 Hz to the low field hydrogen at δ 9.29 which splits each of the seven peaks into doublets. [Note: While these doublets may appear to be triplets upon expansion, the left hand peaks are weak and are due to a phasing problem.] The low field signal is due to an aldehyde resonance. The ¹³C NMR spectrum contains only three signals: 204.1, 40.5, and 14.9 ppm the low field signal is the carbon of the aldehyde. Return to Menu.