Asymmetric Amine-Intercepted Nazarov Cyclization

摘要

We have demonstrated the first asymmetric version of the amine-interrupted Nazarov cyclization process. This reaction furnishes diastereomerically pure products. The success of the whole process relies on the ease with which allenyl vinyl ketones undergo the Nazarov cyclization in the presence of even the weakest acid catalysts, the tolerance of the system to acid-labile functional groups, and the isomerization of the propargyl vinyl ketones which may result in formation of single axial isomers of the intermediate allenyl ketones. This tandem process is likely to have utility in total synthesis.