Diels-Alder cycloaddition of electrophilic 2H-azirines with 3-(3-(tert-butyldimethylsilyloxy)buta-1,3-dienyl)oxazolidin-2-ones. Treatment of the cycloadducts under acidic conditions

3-(3-(tert-Butyldimethylsilyloxy)buta-1,3-dienyl)oxazolidin-2-one was reacted with several electrophilic 2H-azirines to give the expected cycloadducts in moderate to good yields. Treatment of the cycloadducts under acidic conditions gave six-membered ring aminoenones and aziridine derivatives. In the case where anilinium fluoride was used an inversion at the C-2 stereogenic center was observed forming an isomer of the former cycloadduct. The chiral (R)-3-(3-(tert-butyldimethylsiloxy)buta-1,3-dienyl)-4-phenyloxazolidin-2-one was also reacted with an electrophilic 2H-azirine. The reaction showed no diastereoselectivity, but both diastereoisomers were fully isolated by chromatography.