Abstract
In multistep syntheses of complex natural products, selection of the most suitable protecting group for each hydroxy function is very important and sometimes holds the key to success. We are interested in the chemoselective deprotection to expand synthetic applicability of phenyliodine(III) bis(trifluoroacetate) (PIFA). The hypervalent iodine reagent such as PIFA is one of the promising reagent for development of environmentally benign oxidations. We describe not only the deprotection of more readily removable 3,4-dimethoxybenxyl (3,4DMB) protecting groups, but also selectivity among the three benzyl-type protecting groups, 3,4DMB, p-methoxybenzyl (PMB) and benzyl (Bn). When the tetra-protected compound (having Bn, PMB and 3,4DMB groups) was treated with 2.0 equivalents of PIFA at room temperature, the 3,4DMB group was removed to give mono-alcohol with more than 97% selectivity.
