Lewis acid-catalyzed three-component condensation reactions of aldehydes, alkoxysilanes, and propargylsilane: synthesis of α-allenyl ethers

For simultaneous construction of a polyether backbone and the allenyl side chains, Lewis acid-catalyzed three-component condensation reactions of aldehydes, alkoxytrimethylsilanes, and 1-trimethylsilyl-2-butyne were studied. The reaction of these three compounds took place in the presence of a catalytic amount of TrClO4 at −78°C to yield the corresponding α-allenyl ethers in good yields. This reaction was also applied to the synthesis of a polyether having allenyl side chains.