dditive such as TMOF, molecular sieves, and the like, in the presence of a reducing agent such as sodium triacetoxyborohydride, sodium cyanoborohydride, and the like, to yield the corresponding compound of formula (DXXI). [0195] The compound of formula (DXXI) is cleaved from the solid support with a cleaving cocktail such as 25% trifluoroacetic acid in methylene chloride, dichloroethane, and the l