Electrophilic Cyclization and Intermolecular Acetalation of 2‑(4-Hydroxybut-1-yn-1-yl)benzaldehydes: Synthesis of Diiodinated Diepoxy­dibenzo­[c,k]­[1,9]­dioxacyclo­hexa­decines

An expedient strategy for the preparation of diiodinated diepoxy­dibenzo­[c,k]­[1,9]­dioxa­cyclo­hexadecines from readily available 2-(4-hydroxybut-1-yn-1-yl)­benzaldehydes through electrophile-triggered tandem cyclization/intermolecular acetalation sequence has been presented. The electrophilic macrocyclization can be performed under mild conditions and in up to gram quantities. Moreover, palladium-catalyzed coupling and reduction reactions of the resulting iodides could efficiently afford oxa-macrocycles.