Intramolecular reaction

About: Intramolecular reaction is a research topic. Over the lifetime, 5015 publications have been published within this topic receiving 138213 citations.

A facile synthesis of bicyclo[m.n.1]alkan-1-ols. Evidence for organosamarium intermediates in the samarium(II) iodide promoted intramolecular Barbier-type reaction

Abstract: Samarium(II) iodide (SmI 2 ) has been successfully employed as a reductive coupling agent for the intramolecular Barbier-type synthesis of bicyclo[m.n.1]alkan-1-ols. Thus, a variety of 3-(ω-iodoalkyl)cycloalkanones, upon treatment with SmI 2 and a catalytic quantity of iron complex in tetrahydrofuran (THF), provide the title compounds in excellent yields. The reaction is quite general for the construction of diverse bicyclic ring systems, including the highly strained bicyclo[2.1.1]hexan-1-ol

Stereocontrol in intramolecular hydrosilylation of allyl and homoallyl alcohols: a new approach to the stereoselective synthesis of 1,3-diol skeletons.

Abstract: 31.30; H, 5.22; N, 36.52. Found: C, 31.34; H, 5.25; N, 36.70. Low-resolution mass spectral analysis showed the expected molecular ion at m / e 345. The infrared spectrum contained a cyano stretching peak at 2180 cm-'. The 31P NMR spectrum consisted of a singlet at -7.8 ppm. Crystals suitable for X-ray analysis were grown by slow evaporation of a solution of 2 in hexane. The structure of 2 is illustrated in Figure 2, and important structural parameters are given in Table I.9 Both compounds, 1 and 2, are stable in contact with the atmosphere and are unaffected when heated to moderate temperatures. The X-ray structural information for both 1 and 2 is consistent with a cyano rather than an isocyano arrangement,1° and this is confirmed by the infrared spectra.\" The triple bonds of the cyano groups in 2 are slightly longer than that in 1, but no evidence could Figure 2. ORTEP representation of the structure of non-gem-trans-tris(dimethy1amino)tricyanocyclotriphosphazene (2).

Endocyclische SN‐Reaktionen am gesättigten Kohlenstoff? Vorläufige Mitteilung

Abstract: Fig. 1 illustrates a definition of the terms endocyclic and exocyclic SN-reactions, referring to intramolecular nucleophilic substitution processes that occur by an SN2-analogous mechanism. Crossing experiments show that the methyl transfer I II (see scheme 1) does not follow the formally appealing mechanism of the endocyclic SN-process III; the reaction proceeds intermolecularly under all conditions investigated. Kinetic measurements indicate that the methyl transfer XI XII (see scheme 3) occurs in a similar fashion. This behaviour is believed to follow from the preference of tetrahedral carbon for backside attack by the nucleophile in SN2-reactions. The general experience, according to which intramolecular reaction paths over cyclic transition states with ring sizes of 5 or 6 are preferred to their intermolecular counterparts, is not to be extrapolated to SN2-reactions at tetrahedral carbon.

O-arylation versus C-arylation: copper-catalyzed intramolecular coupling of aryl bromides with 1,3-dicarbonyls.

Abstract: The copper-catalyzed intramolecular coupling of aryl bromides with 1,3-dicarbonyls via a six-membered ring closure was examined. With CuI (10 mol %) as the catalyst, N,N‘-dimethylethylenediamine as the ligand, and Cs2CO3 as the base, the reactions of α-(2-bromobenzyl)-β-keto esters in THF at refluxing temperature afforded the corresponding substituted 4H-1-benzopyrans in high yields via O-arylation. On the other hand, the reactions of δ-(2-bromophenyl)-β-keto esters in refluxing dioxane led to the formation of 3,4-dihydronaphthalen-2(1H)-one derivatives via C-arylation.

Stereoselective intramolecular bis-silylation of alkenes promoted by a palladium-isocyanide catalyst leading to polyol synthesis

Abstract: Stereoselective Intramolecular Bis-Silylation of Alkenes Promoted by a Palladium-Isocyanide Catalyst Leading to Polyol Synthesis