The most efficient method for the synthesis of the trans/threo/trans‐bis(tetrahydrofuran) (THF) ring unit was established, and the first total synthesis of (−)‐asimilobin and its diastereomer was then accomplished in twelve and fourteen steps, respectively, from trans‐1,5,9‐decatriene, by a convergent route with a Wittig reaction as the key step. By virtue of these synthetic results, the absolute configuration of the bis(THF) unit in naturally occurring asimilobin should be corrected.