Lithium diisopropylamide in the presence of catalytic amts. of potassium tert-butoxide smoothly converts homoallyl or homobenzyl type ethers to dienes or styrenes. g,d-Unsatd. acetals give 1,3-dienyl ethers and 4-alkylidenetetrahydropyrans or dihydropyrans produce a variety of dienols. If there is a choice, the new double bond is formed with high trans selectivity while the configuration of existing double bonds is retained. The elimination mode is syn-periplanar and concerted, though E1cb like. [on SciFinder (R)]