Lewis acid catalyzed reactions of acetylenic esters with alkenes. Stereochemistry and regiochemistry

Snider, Barry B.; Roush, David M.; Rodini, David J.; González, D.; Spindell, David K.

doi:10.1021/jo01302a007

Cited by 54 publications

(16 citation statements)

References 4 publications

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“…Similar results have been reported by Snider et al using propiolate esters as enophiles (7); since our submission of this manuscript they have also published an account of related work using DMAD (8). Although we obtained la and 3 in 55-60% yield our isolated yield of pure l b was low (28%) and by-products included 2b (17%) and 66 (8%).…”

Section: Tenessupporting

confidence: 89%

Applications of the ene reaction. Synthesis and properties of substituted α-methylene-γ-lactones

Hanson¹,

Mcculloch²,

McInnes³

1981

Can. J. Chem.

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Can. J. Chem. 59,288 (1981). Substituted dimethyl 1,4-pentadiene-l,2-dicarboxylates (1 or 3) may be prepared by A1C13-promoted or thermal ene reaction of olefins with dimethyl acetylenedicarboxylate. Lactonization of these adducts is catalyzed by acid. In the presence of 80% H2S04 the predominant product (ca. 80%) is a (Z)-dihydro-3-carbomethoxymethylene-2(3H)-fi1ranone (2 or 4). Cyclization with anhydrous HCI affords a mixture of products, the composition of which depends on the starting material; major products include the corresponding ( a -and 6-lactone isomers (6 and 7). Detailed lH and 13C nmr data are reported for all compounds. The structures of the (a-4,5,5-trimethyl-, (a-4,5,5-trimethyl-, and (a-4,4,5,5-tetramethyl Chem. 59,288 (1981). Les pentadiene-1,4 dicarboxylates-1,2 de dimethyle substituks (1 ou 3) peuvent Ctre prepares par une reaction h e favoriske par AICI, ou par une reaction thermique des olefines avec I'acetylenedicarboxylate de dimethyle. L'acide catalyse la lactonisation de ces adduits. En presence de H2S04 2 80%, les produits majoritaires (ca. 80%) sont les (Z) dihydrocarbomCthoxymethylene-3 (3H)-furannones-2 (2 ou 4). La cyclisation par du HCI anhydre conduit a un melange de produits dont la composition depend du produit de depart; les produits principaux comprennent les isomeres (E) et les 6-lactones correspondants (6 et 7). On rapporte les donnees dCtaillees de la rmn du 'H et du 13C de tous les composes. Utilisant la diffraction des rayons-X, on a determine les structures des derives des [Traduit par le journal] IntroductionAs an extension of our studies on the effect of Lewis acids on Diels-Alder additions of dimethyl acetylenedicarboxylate (DMAD) (2), we have investigated the effect of AlCl, on ene reactions involving this compound. As anticipated, the Lewis acid causes dramatic acceleration of the reactions of DMAD with various olefins, and is particularly useful in the case of volatile olefins (see below). The adducts 1 are structurally suited as intermediates for the synthesis of substituted a-methylene-y-lactones, which are potential antitumor agents (refs. 3, 4, and references therein) and in which there has thus been considerable recent synthetic interest (5, 6). Our observation of such compounds as by-products of certain AlCl,-promoted reactions encouraged us to undertake a detailed study of the effect of acids on adducts 1.

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Section: Tenessupporting

confidence: 89%

Applications of the ene reaction. Synthesis and properties of substituted α-methylene-γ-lactones

Hanson¹,

Mcculloch²,

McInnes³

1981

Can. J. Chem.

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“…Consequently, the possibility of generation of the L3Cr(CO) 3 molecule, which can produce (q6-PhC-~-=CCI)Cr(CO)] by replacing readily leaving ligands L, under mild conditions is of paramount importance for accelerating this reaction (see Scheme 4, stage b). The validity of this suggestion was confirmed by the fact that reaction (5) was accelerated upon addition of catalytic amounts of (q6-naphthalene)triearbonylchromium (20) as well as by the fact that this reaction was accelerated when acetonitrile was used as the solvent instead of THF.…”

Section: Reactions Of Carbonylmetailate Anions With Phenylethynyl Chlmentioning

confidence: 85%

“…in the presence of (~6-Ct0Hs)Cr(CO) 3 (20). A. PhC~CCI (0.082 g, 0.6 mmol) and complex 20 (10,-~ 0.016 g, 0.06 mmol) were added with stirring at room temperature to a solution of anion 1, which was prepared from 30 (0.18 g, 0.3 mmol) in THF and filtered.…”

Section: Russmentioning

confidence: 99%

Reactions of carbonylmetallate anions with 1-haloalkynes

et al. 1999

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ul. Vavilova, 117813 Moscow, Russian Federation. Fax: + 7 (095) 5085The main regularities of the reactions of l-haloalkynes RC~CX with carbonylmetallate anions [('qS-CsR'5)(CO)3M]-(R" = H (1--3), M = Cr (1), M = Mo (2), or M = W (3); R' = Me (4-6), M = Cr (4), M = Mo (5), or M = W (6)) were revealed. It was established that the first stage of the reactions of anions 1--6 with bromo-or iodoalkynes RC~CX (X=Br or I) involved the transfer of the halogen atom from the sp-hybridized carbon atom to the transition metal atom to form carbonyl halides (rls-CsR'5)(CO)3MX. To the contrary, the reactions of anions 1--6 with chloroalkynes RC~CCI proceeded selectively as a nucleophilic substitution at the unsaturated carbon atom, the reaction rate being governed by the nucleophilicity of the carbonylmetallate anions and the electron-withdrawing ability of the R group. These reaction paths are consistent with the structures of the lowest unoccupied molecular orbitals (LUMO) in the PhC~CX molecules (X = CI, Br, or 1) calculated by the MNDO/PM3 method. In the case of the reactions of l-chloroheptyne-I CIC~CCsHI]n , anions 1--3 appeared to be insufficiently nucleophilic, but these reactions can be performed as cross-coupling of the carbonylmetallate anions with chloroalkynes catalyzed by palladium complexes.Key words: e-ethynyl complexes of chromium, molybdenum, and tungsten, l-haloatkynes, carbonytmetallate anions of chromium, molybdenum, and tungsten.Bifunctional l-haloalkynes RC=CX can react with transition-metal complexes either at the carbon--halogen or at the triple carbon--carbon bond. Examples of formation ofrl2-haloalkyne, halovinylidene, o-l-alkynyl, and tetrahalometallacyclopentadiene complexes of transition metals in reactions of haloalkynes with various organometallic substrates were reported in the literatu re. ! Although haloalkynes are promising ligands, their coordination chemistry remains poorly studied. The reactions of nucteophilie substitution of the halogen atom in 1-haloalkynes are often used to form carbon--heteroatom (oxygen, sulfur, nitrogen, phosphorus, etc.) bonds. 2 However, these reactions have virtually not been used to form transition metal--carbon ,-bonds. The available examples of these processes concern the reactions of carbonylmetallate anions I(nS-CsHs)M(CO)3] -(M = Cr, Mo, or W) with PhC-=-CBr 3, and XC~CX (X =-CI; Br,or-l); 4 thereactionsof[CO)sM-(M =Mn or Re) with IC-=CI, s and the reactions of anionic phthaIocyanine rhodium complexes with RC-=CBr (R = Ph or Prn). 6 Results and DiscussionWith the aim of revealing the regularities and synthetic possibilities of the reactions of carbonylmetallate anions with l-haloalkynes-1, in this work we studied the reactions of anions 1--6 with RC~CX (R = Ph and X = CI, Br, or 1; R = CsHll n and X = CI or Br; or R = COOMe and X = CI): The reactions of anions 1--3 with phenylethynyl halides PhC=CX (X = CI, Br, or I) were studied in close detail. The course of the reaction and the composition of the reaction products are governed by the nature of M, X, an...

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“…Alkenes containing strong electron-donating substituents ( NR 2 , OR) at the C=C bond react with electron-withdrawing alkenes and acetylenes to form cyclobutanes and cyclobutenes [8,9]; however, these reactions proceed with a considerable asymmetry of the transition state and cannot be considered as concerted processes. In certain cases, the addition of acetylenes to alkenes is catalyzed by aluminum chloride and ethylaluminum dichloride [10,11], as well as by transition metal complexes [12,13]. Polyhalogenated alkenes were also reported to participate in [2 + 2] cycloaddition reactions, which occurred under severe conditions via a radical mechanism [14].…”

mentioning

confidence: 99%

Synthesis and Unusual [2 + 2] Cycloaddition Reactions of 1-Trifluoroacetyl-2-haloacetylenes

2005

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Lewis acid catalyzed reactions of acetylenic esters with alkenes. Stereochemistry and regiochemistry

Cited by 54 publications

References 4 publications

Applications of the ene reaction. Synthesis and properties of substituted α-methylene-γ-lactones

Applications of the ene reaction. Synthesis and properties of substituted α-methylene-γ-lactones

Reactions of carbonylmetallate anions with 1-haloalkynes

Synthesis and Unusual [2 + 2] Cycloaddition Reactions of 1-Trifluoroacetyl-2-haloacetylenes

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