The present invention relates generally to nucleic acid chemistry and to the chemical synthesis of oligonucleotides. More particularly, the invention relates to improved methods for synthesizing oligonucleotides wherein periodate salts are used (e.g., in organic solvents) as an oxidation reagent in oligonucleotide synthesis (e.g., for automated phosphoramidite synthesis of oligonucleotides). The invention finds utility in the fields of biochemistry, molecular biology, and pharmacology, and in medical diagnostic and screening technologies.