Regioselective synthesis of C-13(1)-labeled 2-deoxyribonolactones

Syntheses of the five regioselectively C-13(1)-labeled 5-O-benzyl-2-deoxyri bonolactones are described. C-13(1)-Labeled deoxyribonolactones were prepar ed by addition of KCN to epoxides 7 and subsequent lactonization of the res ulting nitriles. Integration of the independent schemes leading to the five isotopomers of 9 results in an efficient and cost effective preparation of labeled mixtures of C-13 mono-labeled deoxyribonolactones. These mixtures are the pivotal intermediates in the preparation of 'population labeled' C- 13-labeled nucleoside phosphoramidites for solid-phase oligonucleotide synt hesis. (C) 2001 Elsevier Science Ltd. All rights reserved.