Access to a Guanacastepene and Cortistatin-Related Skeleton via Ethynyl Lactone Ireland-Claisen Rearrangement and Transannular (4 + 3)-Cycloaddition of an Azatrimethylenemethane Diyl. - Zhurakovskyi, Oleksandr; Ellis, Sam R.; Thompson, Amber L.; Robertson, Jeremy (Organic Letters, 2017)