Straightforward synthesis of labeled and unlabeled pyrimidine d4Ns via 2′,3′-diyne seco analogues through olefin metathesis reactions

The synthesis of dideoxynucleosides (ddNs) or didehydro-dideoxynucleosides (d4Ns) from nucleosides has been extensively reviewed. While previously described methods are based on the modification of the 2'- and/or T-OH group of the intact ribose moiety, the use of a ring-closing metathesis (RCM) for the formation of the unsaturated cyclic system of nucleosides could be a straightforward approach to the d4Ns. Thus, as part of our drug labeling program, this paper reports a straightforward synthesis of 2',3'-didehydro-2',3'-dideoxyuridine (d4U) and [1',2',3',4',5'-C-13(5),6-C-13,1,3-N-15(2)]d4T using the RCM protocol. This paper discusses the preparation of nucleoside dienes and the activity of ruthenium-based metathesis catalysts. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).