A rapid internucleotide bond formation for the phosphotriester approach by use of new condensing reagents

Bis(2,4,6-trihalophenyl) phosphorochloridates (TCP and TBP) were found to be effective as condensing reagents for the rapid internucleotidic phoshotriester bond formation. The benzoyl group as the N3-imide protecting group of thymidine was also useful for prevention of the side reaction caused by the active condensing reagents.