Abstract
The synthesis of 2‐oxa‐7‐thia‐isotwistane (11) and 2‐oxa‐7‐thia‐twistane (22) as well as of several of their derivatives is described starting from endo‐2‐hydroxy‐9‐thiabi cyclo[3.3.1]non‐6‐ene (4).The 10O(2)‐isotwistane bromide 13, iodide 14 and tosylate 30 as well as the 10S(7)‐isotwistane iodide 15, tosylate 20, and the 10S(7)‐twistane tosylate 21 were treated under reaction conditions suitable for molecular rearrangements involving the epi‐sulfonium ion i and the oxonium ion g. respectively, by neighbouring group participation.