A simple and efficient chemoselective method for the catalytic deprotection of acetals and ketals using bismuth trifiate

Bismuth triflate is a highly efficient catalyst (0.1-1 mol %) for the deprotection of acetals and ketals. The procedure is very facile and selective for acetals derived from ketones and conjugated aldehydes. tert-Butyldimethylsilyl ethers are stable to the reaction conditions. The highly catalytic nature of bismuth triflate and the use of a relatively nontoxic solvent system (THF/H₂O) make this procedure particularly attractive for large-scale synthesis.