Intermolecular reactions of N-alkoxycarbonyliminium ions with propargyltrimethylsilane; oxazinone versus allene formation

Article abstract of DOI:10.1016/0040-4020(92)85018-A

Intermolecular reactions of N-alkoxycarbonyliminium ions with propargyltrimethylsilane mainly lead to 6-(trimethylsilyl)methyl-3,4-dihydro-2H-1,3-oxazinones, formed by intramolecular trapping of a stabilized β-sily vinylic cation. α-Allenyl carbamates are obtained as minor products. The oxazinone/allene ratio is dependent on the nature of the Lewis acid and the solvent used.