Abstract The molecular structures of α-methylbenzyl methacrylate, 1,2-diphenylethyl methacrylate, α-t-butylbenzyl methacrylate, 1,2,2,2-tetraphenylethyl methacrylate, diphenylmethyl methacrylate, and 1,1-diphenylethyl methacrylate in solution were investigated by means of IR spectroscopy and 1H NMR spectroscopy using a lanthanoid-induced chemical shift (LIS) reagent [Eu(fod)3] by reference to X-ray analysis data. The preferred conformation between the C=C double bond and the C=O group was estimated to be s-cis in solution. The conformation of ester groups of α-substituted benzyl methacrylates in toluene depended upon the α-substituent and the temperature. On the basis of structural data, the mechanism of the highly enantiomer-selective polymerization of racemic methacrylates with a (−)-sparteine-Grignard reagent complex is discussed.