Abstract A number of 3-triorganosilyl-and 3-trimethylgermyl-2, 5-dihydrofurans have been prepared by the cyclization of 2-triorganosilyl (germyl)-2-butene-1, 4-diols obtained from the hydrosilylation and hydrogermylation products of 1, 4-bis (trimethylsiloxy)-2-butyne. It has been found that the liquid-phase heterogeneous hydrogenation of these compounds over palladium catalysts is accompanied by simultaneous isomerization and disproportionation ...