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Selective Hydrogenation of Avermectin Catalyzed by Iridium‐Phosphine Complexes
Author(s) -
MA XiaoYan,
WANG Kun,
ZHANG Lei,
LI XianJun,
LI RuiXiang
Publication year - 2007
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200790277
Subject(s) - chemistry , phosphine , medicinal chemistry , iridium , catalysis , avermectin , benzene , chelation , triphenylphosphine , tris , organic chemistry , medicine , biochemistry , anatomy
A series of new iridium complexes, IrCl(COD)(TMOPP) ( 1 ) [COD=1,5‐cyclooctadiene, TMOPP=tris(4‐ methoxyphenyl)phosphine], IrCl(COD)(TFMPP) ( 2 ) [TFMPP=tris(4‐trifluoromethylphenyl)phosphine], IrCl‐ (COD)(BDNA) ( 3 ) [BDNA=1,8‐bis(diphenylphosphinomethyl)naphthalene], IrCl(COD)(BISBI) ( 4 ) [BISBI=2,2′‐bis(diphenylphosphinomethyl)biphenyl] and IrCl(COD)(BDPB) ( 5 ) [BDPB=1,2‐bis(diphenylphosphinometh‐ yl)benzene], were synthesized and characterized by NMR spectra and elemental analyses. In order to obtain the relationships between complex structures and their catalytic properties, IrCl(COD)(DPPM) ( 6 ) [DPPM=bis(diphenylphosphino)methane], IrCl(COD)(DPPE) ( 7 ) [DPPE=1,2‐bis(diphenylphosphino)ethane], IrCl(COD)(DPPP) ( 8 ) [DPPP=1,3‐bis(diphenylphosphino)propane] and IrCl(COD)(TPP) ( 9 ) [TPP=triphenylphosphine], were also synthesized according to the reported methods. The hydrogenation results showed that the low electronic density at the central metal was favorable to increase the catalytic activity for the hydrogenation of avermectin, but decrease the selectivity to ivermectin. The complex with a large chelating ring and a bulky chelating backbone would easily cause the cleavage of CO bond in avermectin to give a byproduct avermectin aglycon.