Dimethylaluminum Chloride Research Articles

Darstellung, Eigenschaften und Molekülstrukturen von Alkylaluminiumaminoalkoxidchloriden

Alkylaluminium aminoalkoxide chlorides [R(Cl)AlOR*] 1-3 have been obtained from the reaction of dialkyl aluminium chlorides R2AlCl with the respective aminoalkohol HOR* (1: R = Et, OR* = dimethylamino-1-propanol; 2: R = Me, OR* = (+);(-)-dimethylamino-2-propanol; 3: R = Me, OR* = (S)-N-methyl-2-pyrrolidinyl-methanol). The reaction between dimethylaluminium chloride and (S)-alpha,alpha-diphenyl-2-pyrrolidinyl-methanol (OR* = Dpm) yielded, by contrast, the ionic {[MeAl(OR*)(2)AlMe2](+) [MeAlCl3](-)} complex (4). 1-4 have been characterised by H-1,C-13 and Al-27-NMR spectroscopy. Crystal structures of 1 and of the 1:1 solvate of 4 with Et2O have been determined by X-ray methods and the absolute structure of 4 was confirmed by refinement of the Flack-parameter. The dimeric molecules of 1 are composed of two chelating rings linked via an almost planar Al2O2 unit and pentacoordination is observed about aluminium. In contrast, each of the two crystallographically independent cation molecules of 4 contains one four- and and one five-coordinate metal centre.

Phorboxazole synthetic studies. 1. Construction of a C(3-19) subtarget exploiting an extension of the Petasis-Ferrier rearrangement.

[formula: see text] In this, the first of two letters, we outline our overall strategy for the total synthesis of phorboxazoles A (1) and B (2), rare oxazole-containing macrolides possessing extraordinary antimitotic activity, and describe the assembly of a C(3-19) subtarget (-)-5 for the total synthesis of phorboxazole A. The synthesis of (-)-5 was achieved in 15 linear steps (12% overall yield), exploiting a modification of the Petasis-Ferrier rearrangement to construct the C(11-15) cis-tetrahydropyran. Dimethylaluminum chloride (Me2AlCl) proved to be the Lewis acid of choice for the Petasis-Ferrier rearrangement.

ChemInform Abstract: Chelate‐Controlled Carbonyl Addition Reactions. The Exceptional Chelating Ability of Dimethylaluminum Chloride and Methylaluminum Dichloride.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chelate-controlled carbonyl addition reactions. The exceptional chelating abilityof dimethylaluminum chloride and methylaluminum dichloride

Highly selective chelatinn-controlled aldol and allyl nucleophile additions to β-alkoxy aldehydes promoted by dimethylaluminum chloride and methylaluminum dichloride are described. Cationic aluminum chelates are proposed as intermediates in these reactions. Evidence is provided to support the claim that chelate organization with Me 2AlCl and MeAlCl 2 is possible even with β- tert-butyldimethyl-silyloxy groups. Stereoselectivity data comparing the chelating potential of Me 2AlCl, McAlCl 2, SnCl 4, and TiCl 4 is provided.

Chelation-controlled stannylacetylene additions to β-alkoxy aldehydes promoted by alkylaluminum halide Lewis acids

Lewis acid-mediated additions of stannylacetylenes to β-alkoxy aldehydes are reported. High levels of chelation control are observed with dimethylaluminum chloride (Me 2AlCl) and methylaluminum dichloride (MeAlCl 2).

Lewis Acid Mediated Peterson Fluoroolefination

AbstractPeterson olefination of the alkyl and aryl aldehydes with C,O‐bis(triethylsilyl)fluoroketene acetal 1 promoted by titanium tetrachloride and dimethylaluminum chloride was investigated. Desired fluoroolefins were formed with high stereoselectivity and moderate to high yields.

Synthesis of Substituted Pyridines via Regiocontrolled [4 + 2] Cycloadditions of Oximinosulfonates

Diels−Alder cycloadditions of oximinosulfonate 8 with a variety of 1,3-dienes proceed with regiochemistry opposite to that observed with conventional imino dienophiles, providing expeditious synthetic routes to substituted pyridines, tetrahydropyridines, and pyrrolines. The oximinosulfonate 8 is prepared in one convenient synthetic operation from Meldrum's acid and reacts with conjugated dienes at −78 °C in the presence of 2 equiv of dimethylaluminum chloride to afford [4 + 2] cycloadducts in good to excellent yield. Exposure of these cycloadducts to the action of NaOMe and N-chlorosuccinimide in methanol−THF at room temperature then produces substituted pyridines. The utility of this new two-step annulation protocol is demonstrated in total syntheses of the pyridine alkaloids fusaric acid and (S)-(+)-fusarinolic acid. Heating the [4 + 2] cycloadducts derived from 8 in a mixture of acetonitrile and pH 7 phosphate buffer induces an unusual Stieglitz-type rearrangement leading to the formation of interestin...

Efficient method for preparation of N-methoxy- N-methyl amides by reaction of lactones or esters with Me 2AlClMeONHMe·HCl

The reaction of a lactone or an ester with dimethylaluminum chloride and N, O-dimethylhydroxylamine hydrochloride provided an efficient method for preparation of N-methoxy- N-methyl amide.

Novel lewis acid promoted spiroannulation versus [2+2] - cycloaddition of dihydrofuran and dihydropyran to quinones

Dihydrofuran was found to undergo dimethylaluminium chloride promoted [2+2] - cycloaddition with benzo- and naphthoquinone. The first example of a novel spiroannulation was observed with methoxybenzoquinone. With dihydropyran, spiroannulation only, occurred in all cases investigated.

Infrared Spectroscopy of Trimethylaluminum and Dimethylaluminum chloride adsorbed on Alumina

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared Spectroscopy of Trimethylaluminum and Dimethylaluminum chloride adsorbed on AluminaC. Soto, R. Wu, D. W. Bennett, and W. T. TysoeCite this: Chem. Mater. 1994, 6, 10, 1705–1711Publication Date (Print):October 1, 1994Publication History Published online1 May 2002Published inissue 1 October 1994https://doi.org/10.1021/cm00046a024RIGHTS & PERMISSIONSArticle Views478Altmetric-Citations27LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (716 KB) Get e-Alerts Get e-Alerts

UV/VIS‐spektroskopischer Nachweis einer selektiven Komplexbildung zwischen WOCl4 und trimethylaluminium. Ein weg zur Charakterisierung von methylaluminoxanen

AbstractThe kinetic analysis of the reaction between WOCl4 and trimethylaluminium (TMA) shows that TMA forms a 2 : 1 mol/mol‐complex with WOCl4 before it acts as an alkylating agent. The reaction steps can be observed separately because rate constants kcomplex formation ≫ kalkylation and ultraviolet/visible (UV/VIS) absorption coefficients ϵcomplex ≠ ϵWOCl4. The rapid change of the WOCl4‐UV/VIS‐spectrum is typical for TMA and cannot be observed with methylaluminoxane (MAO) or with dimethylaluminium chloride. Due to the selective complex formation it is possible to determine the exact content of “free” TMA in MAO.

Seven‐Membered Heterodimetallic Ring Systems from (Conjugated Diene) Group 4 Metallocene Complexes and Organoaluminium Reagents

AbstractThe (s‐trans/s‐cis‐η4‐butadiene)zirconocene reagent adds dimethylaluminium chloride to yield the heterodimetallacyclic main group/transition‐metal system 2b, containing a seven‐membered metallacyclic framework that exhibits a “π‐agostic” s̀‐allyl zirconium interaction. Similar compounds (2c–f, 5a, 6) are obtained upon reaction of (butadiene)zirconocene with Et2All and (butadiene)hafnocene with Me2AlCl or Et2AlI. Addition of Me2AlCl or Et2AlI to (isoprene)zirconocene proceeds regioselectively to yield the corresponding heterodimetallacycles bearing the methyl substituent at C‐3 (i.e. near to the attached aluminium center). The iodide‐bridged heterodimetallacycles exhibit dynamic NMR spectra that indicate a rapid enantiomerization process on the NMR time scale (ΔG±ent ≈ 11–12 kcal mol−1). It is assumed that this automerization reaction proceeds by rate‐limiting aluminium‐halogen bond cleavage leading to an acyclic mixed metal heterodimetallic intermediate. This process is markedly inhibited by the presence of excess diethylaluminium iodide.

Stereoselective Conjugate Addition of Organoaluminum Chlorides to α,β-Unsaturated Carboxylic Acid Derivatives

Organoaluminum chlorides react smoothly with α,β-unsaturated N-acyloxazolidinones providing chiral β-branched carboxylic acid derivatives. An unexpected contrast between the mode of reaction of dimethylaluminum chloride and that of the higher homologues is observed. While diethylaluminum chloride and its higher homologues react with the acceptors at low temperature via a polar pathway, dimethylaluminum chloride requires activation by UV-light or radical initiation under otherwise identical conditions. With bicyclic oxazolidinones derived from galactosamine a high stereoselection is accomplished in the formation of the branched carboxylic acid derivative.

Discrimination of Reaction Pathways by a Simple Organoaluminum Compound, Me2AlCl, in Lewis Acid Promoted Reactions of Aldehydes with Organosilicon Reagents

Abstract A novel character of a simple organoaluminum compound, dimethylaluminum chloride, concerning molecular recognition is demonstrated by the crossover reaction of aliphatic and aromatic aldehydes (benzaldehyde and cyclohexanecarbaldehyde) with organosilicon reagents, ketene trimethylsilylacetal and cyanotrimethylsilane in the presence of dimethylaluminum chloride (20–50 mol%) to afford the corresponding aldol adduct of benzaldehyde and cyanohydrin of cyclohexanecarbaldehyde exclusively.

Alkylaluminum Chloride Catalyzed Ene Reactions of Formaldehyde with Unsaturated Carboxylic Acids, Esters and Alcohols

Dimethylaluminum chloride and ethylaluminum sesquichloride catalyze the ene reactions of formaldehyde with the C,C-double bond of unsaturated carboxylic acids, for example oleic acid and 10-undecenoic acid, and of the respective alcohols. Ethylaluminum dichloride catalyzes the ene reactions of formaldehyde with the respective carboxylic acid esters.

Reaction of trimethylaluminum with selenium tetrachloride. Synthesis of [(CH3)3 Se][ClAl(CH3)2(Cl)Al(CH3)3]. The first selenium-based liquid clathrate

Selenium tetrachloride reacts with an excess of trimethylaluminum in the presence of aromatic solvents to afford a non-stoichiometric organoaluminum-selenonium based inclusion compound of the formula [(CH3)3Se][ClAl(CH3)2(Cl)Al(CH3)3]·(aromatic solvent) n . The cation of the parent compound of the inclusion complex results from the alkylation of SeCl4 producing the (CH3)3Se+ selenonium ion while the anion consists of a dimethylaluminum chloride unit and a trimethylaluminum unit bridged by a chlorine atom. This liquid inclusion complex, liquid clathrate, can accommodate 8.5 benzene molecules or 8.3 guest toluene molecules per anionic moiety.

ChemInform Abstract: Application of (Chloromethyl)aluminum 2‐(2‐Propenyl)anilide in the Conversion of γ‐ and δ‐Lactones into Protected Hydroxy Acids.

AbstractThe lactones (I) are cleaved in the reaction with the aniline (II) and dimethylaluminum chloride to give the amides (III).

ChemInform Abstract: Novel Route to Selenoketones from Ketones by the Use of Bis(dimethylaluminum) Selenide.

AbstractBis(trimethylsilyl) selenide (I) is treated with two equivalents of dimethylaluminum chloride (II) to form bis(dimethylaluminum) selenide (III) which is an effective agent for the selenation of ketones, e.g. (V), (XI), or (XIV), to give the corresponding selones.

Novel route to selenoketones from ketones by the use of bis(dimethylaluminum) selenide

Bis(dimethylaluminum) selenide, prepared in situ via transmetallation reaction of bis(trimethylsilyl) selenide with dimethylaluminum chloride, reacted with ketones in the presence of a diene to give Diels-Alder adducts of the corresponding selenoketones and the diene.

ChemInform Abstract: Chloromethylaluminum ‐ 2‐(2‐Propenyl) Anilide. A Convenient Reagent for the Conversion of Lactones into Protected Hydroxy Acids.

Abstract2‐Allylaniline (I) reacts with γ‐butyrolactone (II) in the presence of dimethylaluminum chloride to give the amide (IV) after protection of the hydroxy group.