Extension of the 5-alkynyluridine side chain via C–C-bond formation in modified organometallic nucleosides using the Nicholas reaction

• Renata Kaczmarek,
• Dariusz Korczyński,
• James R. Green and
• Roman Dembinski

Beilstein J. Org. Chem. 2020, 16, 1–8, doi:10.3762/bjoc.16.1

• confirmed that the Nicholas reaction can be carried out in a nucleoside presence, leading to a divergent synthesis of novel metallo-nucleosides enriched with alkene, arene, arylketo, and heterocyclic functions, in the deoxy and ribo series. Keywords: alkynes; 5-alkynyluridines; C–C-bond formation; dicobalt

• warranted, which at the same time may provide biologically active compounds. Results and Discussion Preparation of 5-alkynyluridines was carried out from acyl-protected 5-iodouridines (1a,b) [8][63] and the appropriate terminal alkyne in the presence of catalytic amounts of Pd(PPh3)4, copper(I) iodide

• the synthesis of hexacarbonyl dicobalt 5-alkynyluridines (4 or 5): A round-bottom flask was charged under a nitrogen atmosphere with Co2(CO)8 (0.222 g, 0.650 mmol), alkynyl nucleoside 2 or 3 (0.500 mmol), and THF (10 mL). The mixture was stirred at room temperature (22 °C) for 1 h. The solvent was