Hydrolytic procedures for selective 2-debenzoylation and 2,4-dideacylation of 2'-0-tert-butyldimethylsilyl-7-0-(triethylsilyl)taxol are reported. The first synthesis and biological evaluation of a 4-substituted analogue, 4-deacetyl-4-isobutanoyltaxol, is presented. The chemistry described in this letter is suitable for the facile synthesis of taxol congeners modified at C-2 and/or C-4.