Stereoselective accesses to enantioenriched allyl-, allenyl-, and propargyl-silanes via SiSi bond activation by palladium–isocyanide catalysts

Stereoselective synthesis of allyl-, allenyl-, and propargyl-silanes via palladium-catalyzed intramolecular bis-silylation (IBS) is described. IBS of disilanyl ethers of propargylic and allylic alcohols produced bis-silylation products stereoselectively in good yields via formation of 1,2-oxasiletanes as primary products. From the bis-silylation products, allyl-, allenyl-, and propargyl-silanes were synthesized via Peterson-type elimination or acid-catalyzed 1,2-silyl migration. The IBS/elimination as well as the IBS/migration sequences were carried out in one reaction vessel, providing ready access to those synthetically useful organosilicon compounds. Highly enantioenriched allyl-, allenyl-, and propargyl-silanes including polymer-supported derivatives were stereoselectively synthesized by the new methods. Synthetic application of the highly enantioenriched allenyl- and allyl-silanes is also described.