Maren Bode

Catalytic and selective ring expansion reactions of o-phenyl-substituted 2H-azaphosphirene tungsten complexes

Abstract ortho -Phenyl-substituted ethoxy- and aminocarbene pentacarbonyltungsten complexes 2a – c and 3a – c are synthesized and the latter are reacted with chloromethylenephosphane 4 in diethyl ether in the presence of triethylamine to yield the ortho -phenyl-substituted 2 H -azaphosphirene complexes 6a – c via elimination of triethylammonium chloride; remarkable are the prolonged reaction times in the case of the methoxy- and dimethylamino-substituted complexes 6b , c . The 2 H -azaphosphirene complexes 6a – c and 7d are reacted with benzonitrile in dichloromethane in the presence of ferrocenium hexafluorophosphate to furnish the 2 H -1,2,4-diazaphosphole complexes 8a – d ( 8a : R=Me, 8b : R=OMe, 8c : R=NMe 2 , 8d : R=H); the reaction course will be discussed. All complexes were unambiguously confirmed by NMR spectroscopy and elemental analysis and, additionally complexes 2b , 5 and 6b by X-ray analysis.