The present teachings provide methods, compositions, and kits for synthesizing and sequencing nucleic acids. In some embodiments, elaborated nucleotide phosphorothiolate compounds are employed along with efficient cleaving reactions. Improved sequencing efficiency is achieved by the rapid polymerase-mediated incorporation of elaborated nucleotide phosphorothiolate compounds. Increased sequencing efficiency is also achieved by the ability of the cleaving reactions to restore the incorporated nucleotides to their natural structure prior to subsequent elongation.