Ladder polyether synthesis. Artist: V8rik; Wikipedia.
"Furthermore, both increased THP:THF selectivity and increased conversion...correlate with increased water content in the reaction milieu." (Vilotijevic and Jamieson 2007:1190)
"These THP-selective, epoxide-opening cascades are far higher-yielding than those that rely upon covalently attached directing groups...They are high yielding and highly THP-selective...require no directing groups on any of the epoxides, and are most effectively promoted by H2O...per-epoxide yields...do not change as a function of the number of epoxides or the number of THP rings preceding a given epoxide." (Vilotijevic and Jamieson 2007:1191)
"[T]emplated, water-promoted, THP-selective epoxide-opening cascades provide a straightforward means for efficient and rapid assembly of ladder polyethers, enabling investigations directed toward understanding the mode of action of these extraordinary natural products." (Vilotijevic and Jamieson 2007:1192)