One‐Pot Assembly of 7‐Methylene‐6,8‐dioxabicyclo[3.2.1]octanes, Congeners of Frontalin, from Ketones and Acetylene

A facile, consecutive, self‐consisting assembly of two molecules of ketones with two molecules of acetylene to afford 7‐methylene‐6,8‐dioxabicyclo[3.2.1]octanes, which are unknown congeners of widespread insect pheromones, has been discovered. The reaction is realized in a one‐pot procedure in a MOH/DMSO system (M = K, Cs) at 80 °C for 1 h under acetylene pressure or under atmospheric pressure; the isolated yields of the bicycles reached 86 %. The new reaction conceptually contributes to the synthesis of insect pheromones as well as to the chemistry of ketones and acetylene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)