Dynamic 1H NMR study around the heteroaryl–carbon and carbon–carbon single bonds and also around carbon–carbon double bond in a particular phosphorous ylide involving a 2-methyl indole

Abstract For the first time, a series of separate dynamic 1 H NMR effects are reported at different temperatures within a particular phosphorous ylide involving a 2-methyl indole namely dimethyl 2( N -2-methyl indole-1-yl)-3-(triphenyl phosphoran ylidene) butandioate. These effects are attributed to restricted rotation around the heteroaryl–carbon and carbon–carbon single bonds and also around carbon–carbon double bond. Rotational energy barrier (Δ G # ) for their interconversion process of rotational isomers equals (55.33, 49.91 and 70.16) ± 2 kJ mol −1 , respectively.