Lonnberg Harri, Stromberg Roger, Williams Andrew
Department of Chemistry, University of Turku, FIN-20014, Turku, Finland.
Org Biomol Chem. 2004 Aug 7;2(15):2165-7. doi: 10.1039/b406926a. Epub 2004 Jul 5.
A Bronsted graph with a convex break at pK(a)(Lg)= 12.58 provides compelling evidence for an intermediate in the alkaline cyclisation of uridine 3'-phosphate esters. The transient pentacoordinated oxyphosphorane dianion intermediate collapses to reactant and cyclic uridine 2',3'-monophosphate faster than it can pseudo-rotate and isomerise to the 2'-isomer.
