A FACILE PREPARATION OF N-(ISOPROPOXYALKYL) AMIDES BY GENERATION AND TRAPPING OF N-ACYLIMINIUM IONS FROM IONIZATION-REARRANGEMENT REACTIONS OF N-TRIFLYLOXY AMIDES

A series of hydroxamic acids were converted to N-triflyloxy amides which were heated in 2-propanol to give N-(1-isopropoxyalkyl) amides in high yields. The method is simple, direct, and extremely tolerant of structural diversity both in the N-acyl group, as well as in the 1-isopropoxyalkyl group. N-Alkylation of secondary N-(1-isopropoxyalkyl) amides can be used for converting them to tertiary N-(1-isopropoxyalkyl) amides. N-Acyliminium ions of wide structural diversity can be generated easily from N-(1-isopropoxyalkyl) amides available by this methodology.