Showing papers by "Henri Rudler published in 1990"

First intramolecular alkyne–CO insertion reactions in aminocarbene complexes of chromium: formation of condensed heterocycles following extensive hydrogen migrations

Abstract: The aminocarbene complexes (CO)5CrC(Me)[N(Me)(CH2)3CCPh](6) and (CO)5CrC[graphic omitted][(CH2)3CCMe](14) lead, upon heating in benzene, to the polycyclic triple bond and CO inserted products C15H15NO (12) and C12H15NO (19) through multiple C–H activations.

A new reaction of aminocarbene complexes of chromium upon alkyne insertions : deoxygenation rearrangement of ketene intermediates. Formation and X-ray structure of a tetrahydroindolizine complex

Abstract: Aminocarbene complexes (1) of chromium bearing suitable substituents on nitrogen react with alkynes to give, besides the expected heterocyclic compounds (5) and (6) originating from cascade alkyne–CO insertion–rearrangement reactions, deoxygenation–rearrangement products (8) of ketene intermediates, whereas when nitrogen bears substituents of low migratory aptitude, ketene complexes (4) and their derivatives (7) could be isolated and fully characterized either by spectroscopy or by X-ray Crystallography.

Synthesis and Reactivity of Aziridinocarbene Complexes of Chromium and Tungsten: Formation of Nitrile and Acetiminoester Complexes.

Abstract: 2-Methylaziridine H NCH 2 C HCH 3 reacts with alkyl- and aryl-(alkoxy)carbene complexes of chromium and tungsten to give alkyl- and aryl-aziridinocarbene complexes. The latter undergo a thermal transformation to give olefins and alkyl- or aryl-nitrilechromium pentacarbonyl complexes, e.g. (CO) 5 CrNC- o -tolyl (which has been characterized by X-ray crystallography). 2-Phenylaziridine H NCH 2 C HPh in turn reacts with the carbene complexes to give directly styrene and the acetiminoester complexes (CO) 5 WHNC(CH 3 )OCH 2 CH 3 and (CO) 5 CrHNC(CH 3 )OCH 2 -CH 3 . The latter gives, upon hydrolysis (CO) 5 CrNH 3 . The structures of (CO) 5 WHNC(CH 3 )OCH 2 CH 3 and (CO) 5 CrNH 3 have been determined by X-ray diffraction. The mechanisms of the two reactions are discussed.

A New Method for the Determination of the Enantiomeric Purity of Carboxylic Acids: Reaction of Carboxylates with Tris(tetraphenylimidodiphosphinato)praseodymium and X-Ray Structure of a Dinuclear Dicarboxylato Adduct.

Abstract: Tris(tetraphenylimidodiphosphinato)praseodynium reacts with ammonium or potassium salts of carboxylic acids to give dinuclear dicarboxylato complexes, the structure of which has been established and which can be used for the determination of the enantiomeric purity of carboxylic acids.

Thiocarbene Complexes of Chromium: Sulfur to Carbon Migration of an Allyl Group Upon Alkyne Insertion.

Abstract: (CO)5CrC(CH3)S(CH2CHCH2) (7) reacts with diphenylacetylene by insertion of the alkyne and of CO to give the unsaturated thiolactones H2CCHCH3(CH3)- CSC(O)C(Ph)C Ph and CH3(H) CSC(O)C(PhC Ph, the former arising from migration of the allyl group from sulfur to carbon and the latter by loss of the allyl group.

Reactivity of N-Disubstituted Aminocarbene Complexes of Chromium: Nitrogen to Carbon Migration of the Benzyl and Allyl Groups Following Alkyne Insertions.

Abstract: Chromium aminocarbene complexes (CO) 5 CrC(CH 3 )N(CH 2 Ph)(CH 3 ) ( 3 ), (CO) 5 CrC(H)N(CH 2 Ph)(CH 3 ) ( 5 ) and (CO) 5 CrC(H)N(CH 2 CHCH 2 )(CH 3 ) ( 7 ) react with diphenylacetylene in boiling benzene to give, after insertions of the alkyne and CO and migration of the benzyl or the allyl group from nitrogen to carbon, substituted 2- and 3-pyrrolinones ( 10–15 ). The structures of (CO) 5 -CrC(CH 3 )N(CH 2 Ph)CH 3 ( 3 Z ) ( R 0.031 R w 0.030) and of the chromium tricarbonyl complex of the pyrrolinone 10 , (CO) 3 Cr (C 24 H 23 ON) ( 9 ) ( R 0.034 R w 0.035) were determined by the X-ray diffraction.

First Intramolecular Alkyne-CO Insertion Reactions in Aminocarbene Complexes of Chromium: Formation of Condensed Heterocycles Following Extensive Hydrogen Migrations.

Abstract: The chromium carbonyl complex (I) is converted into the aminocarbene complex (IV) which undergoes demetalation and cyclization upon thermolysis, forming the fused pyridine derivative (V).