Diastereoselective and Regioselective Synthesis of Conformationally Restricted Thio‐dioxa‐ and Oxo‐oxathiaphosphorinane Dinucleotides Featuring Noncanonical α/β Torsion Angle Combinations (α,β‐CNAs)

Abstract

Abstract Control of the regioselective cyclisation of a stereodefined 5′‐C‐tosyloxy phosphorothioate dinucleotide unit to provide conformationally restricted dinucleotides of either thio‐dioxa‐ or oxo‐oxathiaphosphorinane types is described. NMR structural analysis of the newly synthesized building units showed the α and β torsional angles to be constrained to noncanonical values { gauche (+), trans } or { anticlinal (–), trans }.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)