Mitsuyo Fukui

Preparation of phosphonium salt type ylide palladium complexes containing cyclic diolefin ligands

Abstract The dimeric η1-ylide palladium complex, [{PhMe2P+CH(SiMe3)}Cl2Pd−]2 (I), prepared in 94% yield from (PhCN)2PdCl2 and PhMe2PCHSiMe3, is converted to a new η1-ylide cyclic diolefin complex; [{PhMe2P+CH(SiMe3)}Cl(diolefin)Pd]-(PF6)− (IIa, IIb), by the abstraction of the chloride anion of I with silver hexafluorophosphate in the presence of 1,5-cyclooctadiene or norbornadiene. Complexes IIa and IIb have a neutral palladium(II) moiety and are regarded as palladium(II)-substituted phosphonium salts.

Insertion of Cyclohexyl Isocyanide into a Palladium Ylide Complex

Abstract Cyclohexyl isocyanide reacted with N-trimethylsilylimino-phosphoranedichloropalladium dimer complex (I) giving monomeric isocyanide coordinated palladium complex (II) as an initial product. Further reaction of excess of isocyanide with (II) resulted in insertion of isocyanide into the palladium-nitrogen bond of complex (II). Carbon monoxide reacted similarly with the complex (I).

Migration of the trimethylsilyl group in silylated acylamides

Variable temperature n.m.r. studies were made for several N-trimethylsilylacylamides R1CO·N(SiMe3)R2(R1= alkyl or aryl, R2= Ph or Me). Based on the careful determination of the values of J29Si–H for the CH3–N proton signals in the case of PhCO·NMe(SiMe3) the non-equivalence of the trimethylsilyl 1H resonances was explained in terms of 1,3-migration of the trimethylsilyl group between the nitrogen and oxygen atoms. A study of the variation of the coalescence temperatures and the activation energies for eight N-phenyl-N-trimethylsilylacylamides RCO·NPh(SiMe3), showed that the basicity of the amide largely determined the rate of 1,3-migration of the trimethylsilyl group.

Reactions of group IV organometallic compounds. Part XIII. Extensive study of the cyclization and insertion reactions of trimethylsilylphosphines with isocyanate

Diphenyltrimethylsilylphosphine was found to be an effective catalyst for cyclization of phenyl isocyanate, affording cyclic dimer and trimer at moderate temperature. An abnormal decarboxylation took place to give diphenylcarbodi-imide and its cyclic trimer above 50°. Evidence for the equilibrium reaction, 3 diphenylcarbodi-imide ⇌ cyclic trimer, was obtained. Phenylbis(trimethylsilyl)phosphine forms a stable 1 : 1 adduct with phenyl isocyanate; its structure is discussed.

Diketen as a butenoic acid synthon in regioselective olefin syntheses

The adduct (2) between diketen (1) and Me3SiCH2MgCl is a versatile methylbutenoic (isoprenoid) acid synthon in allylation with prenyl bromide, in δ-lactone formation with several carbonyl compounds, and in palladium-mediated alkylation.