Diels–Alder cycloaddition reactions of methyl 2-methylthiopenta-2,4-dienoate: a gem- captodative diene reacting as dienophile by its terminal double bond

1989 ◽  
pp. 187-188 ◽  
Author(s):  
Jean-Luc Boucher ◽  
Lucien Stella
Keyword(s):  
Double Bond ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
Terminal Double Bond

Reaktive E =C (p—p)π-Systeme, X Darstellung und Reaktivität von Perfluor-3-phosphapent-2-en / Reactive E = C (p-p)π-Systems, X Preparation and Reactivity of Perfluoro-3-phosphapent-2-ene

1986 ◽  
Vol 41 (8) ◽  
pp. 974-980 ◽  
Author(s):  
Joseph Grobe ◽  
Jürgen Szameitat
Keyword(s):  
Double Bond ◽  
Room Temperature ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
Dilute Solution ◽  
Concerted Mechanism ◽  
Thermal Elimination ◽  
Acidic Compounds ◽  
New Compounds ◽  
First Time

Abstract Perfluoro-3-phosphapent-2-ene F5C2 P =C (F )CF3 (1) has been prepared for the first time by thermal elimination of trimethyltin fluoride Me3SnF from trim ethylstannyl-bis(pentafluoroethyl)- phosphane Me3SnP(C2F5) 2 at 300 °C/10−3 Torr. 1 is found to be less stable than F3CP = CF2 in dilute solution at room temperature, forming several 1,3-diphosphabutane dimers. Reactivity studies accomplished till now include (i) the dienophilicity of 1 in [2+4] cycloaddition reactions with butadiene, 2,3-dim ethylbutadiene, cyclopentadiene, 1,3-cyclohexadiene, 2-methylbutadiene, and 2-methylfuran leading by a concerted mechanism to the Diels-Alder-adducts 2-7 in about 80% yield, (ii) the addition of proton acidic compounds HX (X = OMe, Br, NMe2, NEt2) to the PC double bond affording chiral phosphanes of the type F5C2 P(X)CF(CF3)H [X = OMe (8). Br (9). NMe2 (10). NEt2 (11)]. thus proving a stronger polarity δ+P =δ−C for 1 than for F3CP = CF2. New compounds have been characterized by NMR and MS measurements.

Silaheterocyclen, XIII Erzeugung und Cycloadditionsverhalten von 1,3-Diaza-2,4-disila-und 1.3-Disilacyclobutanen mit exocyclischer SiC-Doppelbindung Silaheterocycles, XIII / Formation and Cycloaddition Reactions of 1,3-Diaza-2,4-disila-and 1.3-Disilacyclobutanes Containing an Exocyclic SiC Double Bond

1992 ◽  
Vol 47 (2) ◽  
pp. 217-230 ◽  
Author(s):  
Norbert Auner ◽  
Erika Penzenstadler
Keyword(s):  
Double Bond ◽  
Diels Alder ◽  
Spiro Compound ◽  
Cycloaddition Reactions ◽  
Temperature Range ◽  
Vinyl Group ◽  
Trapping Agent

The silenes A and B are formed by reacting 1,3-ditbutyl-2,4-dichloro-2,4-divinyl-1,3-diaza- 2.4-disilacyclobutane (2) and 1,3-dichloro-2,4-dineopentyl-1,3-divinyl-1,3-disilacyclobutane (15) with LiBut in n-pentane in the temperature range from −10 to 0 °C. The reaction primarily leads to the corresponding α-lithioadducts (addition of LiBut to the vinyl group of 2 and 15), and with subsequent 1,2-LiCl elimination yields A and B as intermediates. A can be trapped by polar reagents Me3SiX (X = OMe, OSO2CF3) as well as by organic dienes which add across the Si = C bond; in the absence of a trapping agent the spiro compound 6 is isolated. The silenes A and B differ in their cycloaddition behaviour to butadienes, norbornadiene and cyclohexa-1,3-diene: Whereas for A the regioselective [2 + 2]-cycloaddition to yield monosilacyclobutane derivatives is preferred due to electronic reasons, the reaction of B leads mainly to Diels-Alder products. Thus, A is quite comparable in its reactivity to dichloroneopentylsilene, while B reacts like its diorgano substituted analogues R2Si = CHCH2But (R = Me, But or Ph).

π-Facial Selectivity in 1,3-Dipolar Cycloaddition Reactions of α-Methylidene-γ-lactone Substituted by 4-Methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl Group in γ-Position

2002 ◽  
Vol 67 (3) ◽  
pp. 353-364 ◽  
Author(s):  
Petr Melša ◽  
Ctibor Mazal
Keyword(s):  
Double Bond ◽  
Carboxylic Acid ◽  
Nitrile Oxide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Enantiomerically Pure ◽  
Nitrile Imine ◽  
Facial Selectivity ◽  
Excellent Selectivity

Diastereoselectivity of 1,3-dipolar cycloaddition reactions of benzyl azide, diazomethane, a nitrile oxide and a nitrile imine to α-methylidene-γ-lactone dipolarophile was effectively controlled by a bulky γ-substituent, 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl in γ-position of the dipolarophile. The dipoles added from the less hindered face of the double bond with an excellent selectivity. Enantiomerically pure dipolarophile was prepared from the easily available (S)-5-oxotetrahydrohydrofuran-2-carboxylic acid.

Cycloaddition reactions across the carbon-carbon double bond of thiirene 1,1-dioxide

1984 ◽  
Vol 49 (7) ◽  
pp. 1300-1302 ◽  
Author(s):  
Mitsuo Komatsu ◽  
Yasuo Yoshida ◽  
Masatoshi Uesaka ◽  
Yoshiki Ohshiro ◽  
Toshio Agawa
Keyword(s):  
Double Bond ◽  
Cycloaddition Reactions ◽  
Carbon Double Bond

scholarly journals Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

1985 ◽  
Vol 63 (4) ◽  
pp. 993-995 ◽  
Author(s):  
Kazimierz Antczak ◽  
John F. Kingston ◽  
Alex G. Fallis
Keyword(s):  
Double Bond ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Exocyclic Double Bond ◽  
Total Syntheses ◽  
Methyl Group ◽  
Secondary Hydroxyl ◽  
Selective Hydrogenolysis

Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

A New Series of Organocatalysts for Diels-Alder Cycloaddition Reactions and Theoretical Analysis

2011 ◽  
Vol 15 (19) ◽  
pp. 3514-3522 ◽  
Author(s):  
Alessandro Casoni ◽  
Elena Borsini ◽  
Alessandro Contini ◽  
Alessandro Ruffoni ◽  
Sara Pellegrino ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Diels Alder ◽  
Cycloaddition Reactions

1-[(E)-Butadienylsulfonyl]-3,3-dimethylbut-2-yl methacrylate

2006 ◽  
Vol 62 (4) ◽  
pp. o1369-o1370 ◽  
Author(s):  
Matthias Zeller ◽  
Allen D. Hunter ◽  
Paul Sampson ◽  
Nataliya Chumachenko
Keyword(s):  
Solid State ◽  
Title Compound ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
Compound C

The title compound, C14H22O4S, was synthesized as a precursor for intramolecular Diels–Alder cycloaddition reactions. The (E)-buta-1,3-dienyl and methacrylate ester systems adopt an s–trans conformation in the solid state, with the two π units in both cases being almost coplanar.

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