Norman L. Holy

The mannich reaction-II : Derivatization of aldehydes and ketones using dimethyl(methylene)ammonium salts

Abstract Aldehydes and ketones have been converted efficiently to their corresponding Mannich products by various dimethyl(methylene)ammonium salts under a range of reaction conditions. The several methods used to form these derivatives are compared. Excellent approaches to aldehyde derivatives involve treating the enol silyl ether of the carbonyl compound with methyllithium and then an iminium salt, or directly adding the iminium salt to the enol silyl ether. Ketones may be derivatized effectively by treatment with potassium hydride, followed by an iminium salt, or from the enol silyl ether by addition of the iminium reagent. Use of iminium reagents in the Mannich reaction is recommended because the yields are often good and the site of attachment on an unsymmetrical ketone is both predictable and controllable.

Hydrogenation of alkynes with a palladium anchored polystyrene catalyst

Abstract Treating chloromethylated polystyrene beads with anthranilic acid and then palladium chloride gives a material capable of catalyzing the cis-hydrogenation of alkynes. Hydrogenation of phenylacetylene (10mmol) with 0.017 g-atom (based on Pd) of catalyst at room temperature and 30 psig for 7.3 h resulted in 82 % styrene and 14% ethylbenzene. Methylphenylacetylene was converted to cis-1-phenylpropene (60%) and n-propylbenzene (17 %). Several other alkynes were also converted to cis alkenes. The catalyst is less selective than the Lindlar catalyst, but is air stable and stores well.

A Convenient Tertiary Amine Synthesis. Use of Methylenedimethylammonium Trifluoroacetate

Abstract Methylenedimethylammonium trifluoroacetate and related Mannich reagents have received rather little attention in view of the novel applications conceptually possible for these salts.1 Specifically, these reagents offer two potential advantages to the usual approach, enhanced reactivity and employment of aprotic conditions. We wished to explore the latter concept by coupling the title reagent with various organometallic reagents.

Coal liquefaction with soluble transition-metal complexes

Abstract Several transition-metal complexes were tested for their effectiveness in liquefying coal under very mild conditions. Liquefaction was not observed, probably because interaction with the coal deactivates the catalyst.

METALLOCENE COMPLEXES OF CYCLOPENTADIENYL YLIDES

Abstract Several new transition metal complexes of the cyclopentadienyl ylides (CpPPh3, CpSMe2, and CpPy are reported. Reactions of CpSMe2 with MnCl2, FeCl2, CoCl2 and NiX2 (where X=d or Br) leads to complexes in which the ylide:metal halide stoichiometry is 1:1. These complexes are assigned sandwich structures. Reaction of Pd(NO3)2 with CpSme2 yields a very air-sensitive compound having a unique (CpSMe2)3 Pd(NO3)2 stoichiometry. With HgX2 the CpSMe2 HgX2 (where X=Cl, Br, I) derivatives are formed; bonding of the mercury is shown for the iodide derivative to be at C-3 of the cyclopentadienyl ring. Reaction of CpPPh3 with FeCl2 produces two derivatives which appear to have stoichiometrieg unique in iron metallocene chemistry: (CpPPh3)Fe2 Cl4 and (CpPPh3)Fe2Cl4.

Polymer-Bound Phosphine Catalysts

While the theme of this volume is catalysis in a single phase, the principles and dynamics of homogeneous catalysis have impacted other areas of catalysis as well. Today, more than ever, there is an overlapping, a meshing of concepts from homogeneous and heterogeneous catalysis. One of the areas that interfaces both classical divisions is catalysis via polymer-bound transition metal complexes. It is an interface area because catalysts are prepared typically from an organic polymer such as polystyrene and then, after attachment of a ligand, a soluble metal complex is bound. The choice of metal complex is almost always based upon examples from homogeneous catalysis. One of the principal motivations for attaching a soluble complex to a polymer is that catalyst recovery becomes much easier. There are, however, motivations beyond simple recovery considerations for examining the reactions of polymer-bound catalysts. Though the characteristics of the polymer-bound phosphines may be described to a first approximation as being predictable on the basis of the properties, performances, and mechanistic interpretations of the homogeneous analogs, the support often has a significant influence on catalytic activity. For example, a polymerbound catalyst may give a product distribution quite different from that of the soluble catalyst. Moreover, it is often observed that polymer-supported catalysts are less oxygen sensitive than the homogeneous ones.

Analysis of Organic Nitrogen Compounds Using Paired Ion Chromatography. Applications to the Analysis of Coal-Derived Liquids

Abstract Evaluation of HPLC as a possible method by which the nitrogen compounds in coal-derived liquids could be analyzed has met with mixed results. Some chromatography fractions display very different HPLC traces in methanol compared with those obtained in a MeOH-HOAc-PIC mixture, but others are insensitive to the change in eluent. HPLC of several model compounds has revealed basic nitrogen compounds generally have longer retention times in paired ion chromatography (PIC) solutions, but that some actually have shorter times. Heterocyclic nitrogen compounds all give longer retention times in PIC solution than in methanol.

Facile Catalytic Hydrogenation with Nitrogen-Anchored Ligands

The 1960’s and 70’s have seen a great deal of interest in homogeneous catalysis. Early visions of the potential of this area included the possibility of homogeneously performing the bulk of the known heterogeneous catalytic reactions, but performing these at lower temperatures. In this sense homogeneous catalysis has been but partially successful. Several catalysts have been developed which do indeed have exceptional activity, but the range of the types of reactions facilitated by homogeneous catalysts is, at present, somewhat restricted. For example, homogeneous catalysts are particularly effective and attractive for hydrogenation and hydroformylation, but other important ÷processes, such as oxidation1 or dehydrogenation2, have not been greatly affected. Even within areas where homogeneous catalysis is very effective, e. g. hydrogenation, catalysts, in some ways, have been disappointing. Hydrogenation has been most successful with respect to hydrocarbons; other functional groups, such as nitro compounds or nitriles, have not been reduced except by a very limited number of catalysts.