Asymmetric cycloetherification based on a chiral auxiliary for 4-acyloxy-1-butene substrates during oxidation with iodosylbenzene via a 1,3-dioxan-2-yl cation

Reaction of but-3-enyl camphanate and its derivatives with iodosylbenzene yielded tetrahydrofuran-3-yl camphanate with high diastereomeric ratio via a 1,3-dioxan-2-yl cation intermediate. The reaction using (1S)-camphanate as a chiral auxiliary preferentially gave (S)-3-acyloxytetrahydrofuran and (2S,3S)-3-acyloxy-2-silyltetrahydrofuran.