Unusual Oxidation in the Course of Synthesis of N-Confused Nickel Tetrahydrobilins
摘要:
N-confused Tetrahydrobilins rac-16 and rac-17 were prepared to investigate their cyclization directed to the formation of N-confused chlorins. For achieving the desired cyclization the 5'-position of rac-16 respectively rac-17 was activated by an electron withdrawing cyano function and their 2'-positions were blocked by a methyl group. In addition, the insertion of Ni(II) was accomplished for exercising a template effect during the cyclization process, but the formed nickel complexes rac-18 and rac-19 underwent oxidation to yield oxo-tetrahydrobilins rac-20 and rac-21.
Unusual Oxidation in the Course of Synthesis of N-Confused Nickel Tetrahydrobilins
摘要:
N-confused Tetrahydrobilins rac-16 and rac-17 were prepared to investigate their cyclization directed to the formation of N-confused chlorins. For achieving the desired cyclization the 5'-position of rac-16 respectively rac-17 was activated by an electron withdrawing cyano function and their 2'-positions were blocked by a methyl group. In addition, the insertion of Ni(II) was accomplished for exercising a template effect during the cyclization process, but the formed nickel complexes rac-18 and rac-19 underwent oxidation to yield oxo-tetrahydrobilins rac-20 and rac-21.