Use of a solid-supported coupling reagent for a selective phosphitylation of the primary alcohol of N-2-isobutyryl-2'-deoxy or 2 '-O-methyl guanosine

摘要

We have developed a 5'-regioselective phosphitylation of 3', 5'-OH-guanosine derivatives thanks to a solid-supported coupling reagent with either a standard or a bulky phosphine. A 5'-phosphitylation up to a 95% selectivity was obtained with a quantitative conversion of starting nucleoside. After oxidation into thionophosphotriester or phosphotriester by means of solid-supported oxidizers, the 5'-phosphorylated N-2-i-Bu-2'-OMe guanosines were isolated in good yields (70-80%). (c) 2006 Elsevier Ltd. All rights reserved.