Asymmetric induction in silyl nitronate cycloadditions to Oppolzer's chiral sultam derivatives
摘要:
Silyl nitronate cycloadditions to Oppolzer's chiral sultam derivatives, followed by the elimination of the sily alcohols from the resulting N-silyloxyisoxazolidines, provide DELTA-2-isoxazolines in good stereoselectivity (ca. 89/11). The favored transition state is suggested in the light of the X-ray crystal structure of a major cycloadduct.
Asymmetric silyl nitronate cycloadditions with bornane-10,2-sultam derivatives
摘要:
Asymmetric silyl nitronate cycloadditions with N-acryloyl (2R)-bornane-10,2-sultam, N-acryloyl (2S)-bornane-10,2-sultam, and N-methacryloyl (2R)-bornane-10,2-sultam have been studied. The asymmetric silyl nitronate cycloaddition/elimination methodology provides a general route for the asymmetric synthesis of 2-isoxazolines.