Description Application Air- and moisture-tolerant, this (-)-PSI Reagent was developed in the Baran lab for stereocontrolled synthesis of phosphorothioate oligonucleotides. The enantiomer, (+)-PSI Reagent, is also available (cat# ALD00604). The PSI Reagents open access to thiophosphate-based nucleotide molecules with therapeutic promise as demonstrated by the Baran lab in the preparation of pure stereoisomers of cyclic dinucleotides (CDNs) and antisense oligonucleotides (ASOs). Other Notes Unlocking P(V): Reagents for chiral phosphorothioate synthesis PSI on OpenFlask Legal Information PCT/US2019/027256; U.S. Nonprovisional Patent Application #16/382,692