“…In the past few decades, allenes have been extensively explored in cyclization reactions. , Among the substituted allenes, allenoates have found numerous applications in Lewis base-directed cycloaddition/annulation reactions via zwitterionic intermediates by taking Lu’s [3 + 2] cycloaddition as an inspirational finding. − The readily detachable -OAc group in acetoxy allenoates renders this class of compounds as valuable synthons by generating key diene-ammonium/phosphonium intermediates . In Lewis base-mediated/catalyzed annulations, δ-acetoxy allenoates can offer 5–8-membered ring scaffolds by the attack of the nucleophile at the δ- or α-carbon of an electrophilic intermediate, wherein the allenoate part offers 1C - 4C for the framework, but so far none of them utilized acetoxy allenoates as 5C- synthons (Scheme a–b) . Our interest in allene chemistry ,− , prompted us to explore annulations via the diene-ammonium intermediate, and in this context, we envisioned that annulation involving δ-acetoxy allenoate as 5C-synthon via the diene-ammonium intermediate is feasible with a suitable reaction partner such as sulfamidate-derived cyclic imines. , The latter imines have been explored in cyclization/annulation reactions in recent years, with the sulfamidate as a disposable entity in a couple of cases (Scheme c–d) …”