Regioselective cyclocondensation reactions of 1,3-bis(silyl enol ethers) with different mono(silyl enol ethers) provide an elegant approach for the synthesis of various complex carba- and heterocycles from simple starting materials. Salicylates, diarylethers, resorcins and 3-aryl-3,4-dihydroisocoumarins are prepared based on regioselective [3+3] cyclocondensation reactions of 1,3-bis(silyl enol ethers) with 1,1,3,3-tetramethoxypropane, 2-aryloxy-3-(silyloxy)alk-2-en-1-ones, 3,3-dimethoxypentanoyl chloride and 1-hydroxy-5-silyloxy-4-en-3-ones respectively. In addition, 4,5-diaryl-1,2,3-benzenetricarboxylates are prepared by reaction of 4-hydroxycyclopent-2-en-1-one-2-carboxylates with dimethyl acetylenedicarboxylate. In addition, 1-(2,2-dimethoxyethyl)-1,2,3-triazoles are prepared by regioselective copper(I)-catalyzed [3+2] cyclization of 2-azido-2,2-dimethoxyethane with alkynes.
