In the presence of a catalytic amount of TsOH .H2O, hemiacetals derived from (Z)-4-trialkylsilyl-3-buten-1-ols and chloral were cyclized to 2-trichloromethyl-4-trialkylsilylmethyl-1,3-dioxanes in good to high yields. The substrates bearing an allylic substituent achieved high levels of 1,2-asymmetric induction. When the silyl group was a benzyldimethylsilyl group, the products could be efficiently converted to 1,2,4-triol derivatives by oxidative cleavage of the silicon-carbon bond.