A Mild Method for the Generation and Interception of 1,2-Cycloheptadienes with 1,3-Dipoles

1,2-Cycloheptadiene is a strained, transient species that has been underutilized as a synthetic building block. Seven-membered cyclic allenes are mostly known for their propensity to undergo rapid dimerization, and relatively little has been reported regarding their cycloaddition reactivity with 1,3-dienes or 1,3-dipoles. This work describes the trapping of 1-acetoxy-1,2-cycloheptadiene and its unsubstituted counterpart, generated via desilylative elimination, with a range of 1,3-dipolar trapping partners, affording complex polycyclic products with high regio- and diastereoselectivity.