H-1 NMR chemical shifts and proton-proton coupling constants for some 3-substituted 2-methylpropenes [YCH2C(Me)CH2, Y = H, Cl, Br, I, OH, OMe, OEt, SH, SMe, SEt, NMe(2) and NEt(2)] are reported. Resonances of the olefinic protons were assigned through lanthanide-induced shifts. Chemical shifts of the olefinic protons (H-A and H-B) showed a dependence on the substituent at C-3 of the allylic fragment. Long-range allylic coupling constants ((4)J(choid) for H-A and CH2 and H-B and Me;(4)J(transoid) for H-B and CH2 and H-A and Me) were determined by spectral expansion and simulation. (C) 1997 by John Wiley & Sons, Ltd.353147152