Captodative Substitution Research Articles

The influence of captodative effect on the dienophilicity of olefins. The easy diels-alder reaction of α-methylthioacrylonitrile with cyclohexadiene

We show that the cycloaddition of α-methylthioacrylonitrile to cyclohexadiene is faster than that of acrylonitrile. This indicates that the captodative substitution exerts an accelerating effect on the Diels-Alder reaction despite the larger steric bulk of the methylthio group compared to hydrogen.

Captodative Substitution and Cyclopropane Geometry. IV. X‐Ray Structure of 2‐Methylthio‐1‐r‐2‐t‐Dicyano‐1‐Phenylthiocyclopropane

Captodative Substitution and Cyclopropane Geometry. IV. X‐Ray Structure of 2‐Methylthio‐1‐r‐2‐t‐Dicyano‐1‐Phenylthiocyclopropane

Effets de la Substitution Captodative XXX1. Addition Des Radicaux Dérivés de Cétones, D'Aldéhydes et de Formiates À L'α‐Tert‐Butylthioacrylonitrile2

AbstractOxydation of ketones, aldehydes and formiates in the presence of radicophilic olefin α‐tert‐butylthioacrylonitrile 3 with captodative (cd) substitution does not give the usual radical decay products: The radical adducts dimerize, thus building a four carbon‐bridge between the original radicals R°.

Études Structurales en Relation Avec le Concept de Substitution “Capto‐Dative” II. Analyse des déformations moléculaires dans cinq déhydrodimères de formule générale: RCH2 (CN) (SR') C‐C (CN) (SR') CH2R(1, 2)

AbstractThe crystal structures of five 1,4‐butanedinitrile derivatives have been determined using X‐Ray diffractometry in order to study the effects of captodative substitution on molecular geometry. (I) meso 2,3‐diacetonyl‐2,3‐bis (tert‐butylthio)‐1,4‐butanedinitrile, C18H28N2O2S2, is monoclinic, P21/c with a = 9.694(6), b = 10.208(4), c = 10.404(4) Å, β = 97.46(4) º, V = 1020.8(8)Å3, Z = 2. (II) meso 2,3‐bis[(acetylthio)methyl]‐2,3‐bis(tert‐butylthio)‐1,4‐butanedinitrile, C18H28N2O2S4, is triclinic, PI, with a = 12.867(4), b = 11.175(3), c = 10.430(2)Å, α = 90.43(2), β = 54.82(2), γ = 103.61(2) º, V = 1175.8(6)Å3, Z = 2. (III) meso 2,3‐bis(tert‐butylthio)‐2,3‐bis(butyrylmethyl)‐1,4‐butanedinitrile, C22H36N2O2S2 is monoclinic, C2/c, with a = 22.562(6), b = 10.932(4), c = 10.157(4)Å, β = 90.35(4) º, V = 2505.2(8)Å3, Z = 4. (IV) meso 2,3‐bis (tert‐butylthio)‐2,3‐diethyl‐l,4‐butanedinitrile, C16H28N2S2, is monoclinic, P21/n, with a = 10.004(2), b = 13.794(2), c = 6.633(1)Å, β = 95.61(2) º, V= 910.9(3)Å3 Z = 2. (V) dl 2,3‐diacetonyl‐2,3‐bis(methylthio)‐1,4‐butanedinitrile, C12H16N2O2S2, is triclinic, P1, with a = 9.347(3), b = 9.646(1), c = 8.318(2)Å, α = 99.70(2), β = 104.65(2), γ = 99.23(2) º, V = 698.8(3)Å3, Z = 2.The central carbon carbon bond lengths are very long in the five molecules. Mean C‐C distance is 1.593(2)Å. Bond angles around central carbon atom take values between 105 and 115°.

Addition dipolaire-1,3 aux olefines portant une substitution captodative: reactivite comparee des α et des β amino acrylnitriles vis a vis des arylazides.

Arylazides reacted with α amino-acrylonitriles 1 to produce 1-aryl-5-amino-triazoles, and with β amino-acrylonitriles 2 to give 1-aryl-4-cyanotriazoles. Kinetics showed the Hammett ρ to be > o and therefore, these reactions are controlled by LUMOazide-HOMOolefin interaction. Despite the captodative substitution in 1 and 2 (ΔΔ E ≠∼ 500 cal.M −1) does'nt agree with a diradical intermediate.

A theoretical investigation of the structure and reactivity of carbon-centred radicals

Unrestricted Hartree—Fock 4—31G calculations were performed on carbon-centred radicals to analyze the influence of substituents on the static and dynamic properties of these systems. dd-Substituted radicals are not planar and little stabilized. cc (or cd)-Substitution leads to planar systems which are highly stabilized. The formation of σ-radicals by hydrogen abstraction from the parent molecule is characterized by a smaller exothermicity and presumably a higher activation energy than the formation of π-systems. The autoreaction of alkyl radicals substituted by two captor groups is thermodynamically less favoured than their addition to olefins. Capto-dative substitution seems to favour the whole process: 2RH → 2R → RR.

ChemInform Abstract: NEW SYNTHETIC METHOD. 32. CAPTO‐DATIVE SUBSTITUTION. 5. CAPTO‐DATIVE SUBSTITUENT EFFECTS IN SYNTHESES WITH RADICALS AND RADICOPHILES

Chemischer InformationsdienstVolume 11, Issue 12 Reviews ChemInform Abstract: NEW SYNTHETIC METHOD. 32. CAPTO-DATIVE SUBSTITUTION. 5. CAPTO-DATIVE SUBSTITUENT EFFECTS IN SYNTHESES WITH RADICALS AND RADICOPHILES H. G. VIEHE, H. G. VIEHESearch for more papers by this authorR. MERENYI, R. MERENYISearch for more papers by this authorL. STELLE, L. STELLESearch for more papers by this authorZ. JANOUSEK, Z. JANOUSEKSearch for more papers by this author H. G. VIEHE, H. G. VIEHESearch for more papers by this authorR. MERENYI, R. MERENYISearch for more papers by this authorL. STELLE, L. STELLESearch for more papers by this authorZ. JANOUSEK, Z. JANOUSEKSearch for more papers by this author First published: March 25, 1980 https://doi.org/10.1002/chin.198012392Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume11, Issue12March 25, 1980 RelatedInformation