1, 1, 3, 3-Tetraisopropyl-3-(2-(triphenylmethoxy)ethoxy)disiloxane-1-yl (TES) group was designed for solid-phase RNA synthesis as a 5'-O-protecting group, which can be combined with the tetrahydropyranyl group, a 2'-hydroxyl protecting group. The TES group can be selectively introduced to the 5'-hydroxy group of nucleosides and can be easily removed by 0.1M tetrabutylammonium fluoride or 0.01M hydrochloric acid. (C) 1998 Elsevier Science Ltd. All rights reserved.