[1] Univ Coll Dublin, Sch Chem, Ctr Synth & Chem Biol, Dublin 4, Ireland
[2] Univ Coll Dublin, Sch Chem, Beacon Bioecon Ctr, Dublin 4, Ireland
[3] Max Planck Inst Kohlenforsch, D-45470 Mulheim, Germany
[4] Res & Dev, CMC, API Dev, Isotope Chem, Novo Nordisk As, Denmark
[5] Univ Gothenburg, Dept Chem & Mol Biol, Gothenburg, Sweden