¹³C NMR Chemical Shifts of Heterocycles: 3∗

∗For Parts 1,2, see Refs. 5, 6.

. Empirical Substituent Effects in 2-Halomethyl-2-hydroxy-tetrahydrofurans and -5,6-tetrahydro-4H-pyrans

Abstract

Evaluation by empirically derived equations for the Substituent effect (α, β, γ, δ) on the ¹³C NMR chemical shifts for C-2, C-3, C-4, C-5, C-6, the halomethyl-substituted carbon (C-7) and the cyano or oxymic carbon (C-8) in 2-halomethyl-2-hydroxy-tetrahydrofurans 1a-c, 2, 3a, b, 4a and -5,6-tetrahydro-4H-pyrans 5a-c, 6a [with C-2-substituents (R²): CF₃, CCl₃ or CHCl₂, C-3-substituents (R³): CN, C(Me)=NOH, CH=NOMe, C(Me)=NOMe or CH=NOH], taking as reference the 2-trifluoromethyl-2-hydroxy-tetrahydrofuran (la), is reported. From the additivity properties of the α-, β-, γ-, δ-and ∊-effects for each Substituent it is possible to predict the chemical shift of each carbon of the compounds 1–6.

∗For Parts 1,2, see Refs. 5, 6.

Key Words:

• ¹³C NMR of tetrahydrofurans
• ¹³C NMR of tetrahydro-4H-pyrans
• Substituent effects

Notes

∗For Parts 1,2, see Refs. 5, 6.