Dichlorocarbene generated in a two-phase catalytic system reacts with 3-trimethylsilyl-2,5-dihydrofuran to give both possible products of mono-insertion into the CH bond in positions 2 and 5 of the ring, together with a CC bond adduct. Reaction of 2-trimethylsilyl-4,5-dihydrofuran with dichlorocarbene leads to 2,3-dichloro-2-trimethylsilyl-5,6-dihydro-2H-pyran, which is formed via isomerization of
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