A method has been developed to prepare short DNA sequences using light to deprotect a nucleoside 3'-phosphotriester, generating a phosphodiester useful for coupling with a free 5'- OH-nucleotide. The dimethoxybenzoin group is used as the photochemically-removable protecting group for the 3'-phosphate. Cyanoethyl is most effective as the second protecting group on the phosphodiester. Because the method is directed at the preparation and use ...
