Unexpected loss of stereoselectivity in ring-opening reaction of 2-alkoxy-2-thio-1,3,2-oxathiaphospholanes with a pyrophosphate anion.
A reaction of DBU promoted ring opening in nucleoside-3'-O- and nucleoside-5'-O-(2-thio-4,4-pentamethylene-1,3,2-oxathiaphospholane) monomers with a pyrophosphate or a methylenediphosphonate anion proceeds with substantial loss of stereoselectivity. Depending on the absolute configuration of the phosphorus atom, so far widely accepted the stereoretentive mechanism of condensation is accompanied by a stereoinvertive one, most likely employing an intramolecular ligand-ligand exchange in an uncharged intermediate.
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Department of Bioorganic Chemistry, Łodź, Poland.
Piotr
P
Guga
Agnieszka
A
Tomaszewska
D000838:Anions; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry; D011756:Diphosphates / Q000737:chemistry*; D004164:Diphosphonates / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D009711:Nucleotides / Q000737:chemistry*; D017905:Phosphites / Q000737:chemistry; D012266:Ribose / Q000031:analogs & derivatives* / Q000737:chemistry; D013237:Stereoisomerism
D000838:Anions; D019086:Bridged Bicyclo Compounds, Heterocyclic; D011756:Diphosphates; D004164:Diphosphonates; D009711:Nucleotides; D017905:Phosphites; C434797:oxathiaphospholane; C107241:diphosphoric acid; D012266:Ribose; C027474:methylene diphosphonate; C031033:1,8-diazabicyclo(5.4.0)undec-7-ene
P-diastereomers; nucleoside 1-thiotriphosphates; oxathiaphospholane monomers; stereoselectivity