Base-Catalyzed Dehydrogenative Si-O Coupling of Dihydrosilanes: Silylene Protection of Diols

Abstract

The direct dehydrogenative coupling of 1,3-and 1,4-diols and dihydrosilanes is efficiently catalyzed by Cs 2 CO 3 (10 mol%), cleanly affording six-and seven-membered 1,3-dioxo-2-silacycles with dihydrogen as the sole by-product. Conversely, 1,2-diols do not yield the expected 1,3-dioxo-2-silacyclopentanes, essentially forming cyclic disiloxanes instead. Aside from the synthetic convenience, the procedure itself is also useful for straightforward diol derivatization prior to GLC analysis.

Metal-Free Synthesis of 1,3-Disiloxanediols and Aryl Siloxanols

“…Finally, cesium carbonate was investigated, which afforded the highest selectivity for the synthesis of 1,3-disiloxanediol 2d, with 5 mol % affording the highest yield and cleanest reaction (Table 2, entries 7–10). 29…”

Dehydrogenative silylation of cellulose in ionic liquid

“…21 However, unlike the conventional silylating reagents containing a leaving group, the reaction does not proceed solely with hydrosilane, and appropriate catalysts have been developed. Mainly, the transition metal catalysts such as Rh, Ru, Ir, Co, Mn, and Fe, which exhibit excellent catalytic activities, have been developed, [22][23][24] and alkali metals [25][26][27][28][29][30][31][32] and organocatalysts [33][34][35][36][37][38][39] have also been reported in recent years. Even the carbonate salts have been found to act as catalysts, 26,37,40 according to Corriu's pioneering research in the 1970s, the dehydrogenative silylation of alcohol proceeds in alkyl ammonium carboxylate (molten dodecylammonium propionate).…”

“…Mainly, the transition metal catalysts such as Rh, Ru, Ir, Co, Mn, and Fe, which exhibit excellent catalytic activities, have been developed, [22][23][24] and alkali metals [25][26][27][28][29][30][31][32] and organocatalysts [33][34][35][36][37][38][39] have also been reported in recent years. Even the carbonate salts have been found to act as catalysts, 26,37,40 according to Corriu's pioneering research in the 1970s, the dehydrogenative silylation of alcohol proceeds in alkyl ammonium carboxylate (molten dodecylammonium propionate). 25 However, the reactivity with monohydrosilanes, which can be used for polysaccharide ( polyol) modification without crosslinking, has not been investigated in the Corriu's report.…”