Sumario: | A meta effect on the methoxy-group conformation is studied from both an experimental and a theoretical point of view. Experimental NMR data show that, while in m-anisaldehyde (I) both side-chain groups undergo a restricted rotation, in 2,5-dimethoxybenzaldehyde (II) the methoxy group in ring position 5 is held fixed in a cis conformation with respect to the aldehyde group, which, in turn, presents a carbonyl cis conformation toward that methoxy group. PCILO calculations follow quite closely, in a qualitative sense, all observed trends. © 1983 American Chemical Society.
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