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

Radical clocks as probes of 1,4-biradical intermediates in the photochemical cycloaddition reactions of 2-cyclopentenone with alkenes

1990 ◽  
Vol 68 (9) ◽  
pp. 1590-1597 ◽  
Author(s):  
Andreas Rudolph ◽  
Alan C. Weedon
Keyword(s):  
Double Bond ◽  
Rate Constant ◽  
Photochemical Reaction ◽  
Cycloaddition Reactions ◽  
Double Bonds ◽  
Radical Clocks ◽  
Carbon Double Bond

The products of the photochemical reaction of 2-cyclopentenone with 1,6-heptadiene and with vinylcyclopropane have been examined. With 1,6-heptadiene the products were cyclobutanes, which arise from 2 + 2 photocycloaddition between the cyclopentenone carbon–carbon double bond and one of the two terminal double bonds of the heptadiene. The 1,4-biradical that is an intermediate in this reaction contains a derivative of a 1-hexenyl radical; no products derived from cyclization of this intermediate to a cyclopentylmethyl radical were observed. With vinylcyclopropane some of the products isolated also arose from 2 + 2 photocycloaddition; in addition, comparable quantities of products resulting from rearrangement of the intermediate 1,4-biradical were obtained. In this case the initially produced intermediate 1,4-biradical contains a cyclopropylmethyl radical that can rearrange to a homoallylic radical; the products isolated were derived from intramolecular disproportionation in the new 1,7-biradical containing the homoallylic radical. The rate constant for the rearrangement of the cyclopropylmethyl radical to the homoallylic radical is known and was used as a clock to estimate the lifetime of the initially produced 1,4-biradical. The value estimated is of the order of 50 ns. The structures of the products indicate that the initial bonding between the excited cyclopentenone and vinylcyclopropane takes place at both the α-position and the β-position of the enone and not exclusively at the α-position as a recent report claims. Keywords: enone photocycloaddition, 1,4-biradicals, radical clocks.

ChemInform Abstract: CYCLOADDITION REACTIONS ACROSS THE CARBON-CARBON DOUBLE BOND OF THIIRENE 1,1-DIOXIDE

1984 ◽  
Vol 15 (34) ◽  
Author(s):  
M. KOMATSU ◽  
Y. YOSHIDA ◽  
M. UESAKA ◽  
Y. OHSHIRO ◽  
T. AGAWA
Keyword(s):  
Double Bond ◽  
Cycloaddition Reactions ◽  
Carbon Double Bond

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.

scholarly journals RNA-Seq used to identify ipsdienone reductase (IDONER): A novel monoterpene carbon-carbon double bond reductase central to Ips confusus pheromone production

2021 ◽  
pp. 103513
Author(s):  
Katherine E. Fisher ◽  
Richard L. Tillett ◽  
Misha Footohi ◽  
Cody Caldwell ◽  
Juli Petereit ◽  
...  
Keyword(s):  
Double Bond ◽  
Pheromone Production ◽  
Rna Seq ◽  
Ips Confusus ◽  
Carbon Double Bond ◽  
Double Bond Reductase

Reactions of 4-Pyrones with Azomethine Ylides as a Chemo­selective Method for the Construction of Multisubstituted Pyrano[2,3-c]pyrrolidines

Synthesis ◽  
2021 ◽  
Author(s):  
Dmitrii L. Obydennov ◽  
Vyacheslav D. Steben’kov ◽  
Konstantin L. Obydennov ◽  
Sergey A. Usachev ◽  
Vladimir S. Moshkin ◽  
...  
Keyword(s):  
Double Bond ◽  
Ring Opening ◽  
Azomethine Ylides ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Computational Studies ◽  
Carbon Double Bond ◽  
Reactivity Indexes ◽  
Reaction Proceeds

Abstract4-Pyrones bearing electron-donating and electron-withdrawing groups react with nonstabilized azomethine ylides to form pyrano[2,3-c]pyrrolidines in moderate to good yields. The reaction proceeds chemoselectively as a 1,3-dipolar cycloaddition of the azomethine ylide at the carbon–carbon double bond of the pyrone activated by the electron-withdrawing substituent. The reactivity of 4-pyrones toward azomethine ylides was rationalized by computational studies with the use of reactivity indexes. The pyrano[2,3-c]pyrrolidine moiety could be modified, for example by a ring-opening transformation under the action of hydrazine to provide pyrazolyl-substituted pyrrolidines.

ChemInform Abstract: Electrooxidative Fission of Carbon-Carbon Double Bond in a K2OsO2(OH)4/ HIO4 Double Mediatory System.

ChemInform ◽  
2010 ◽  
Vol 27 (5) ◽  
pp. no-no
Author(s):  
H. TANAKA ◽  
R. KIKUCHI ◽  
M. BABA ◽  
S. TORII
Keyword(s):  
Double Bond ◽  
Carbon Double Bond

Unusual carboncarbon double bond cleavage in thiophenohomotropone system promoted by ethanedithiol

1982 ◽  
Vol 23 (28) ◽  
pp. 2859-2862 ◽  
Author(s):  
Bernard Hanquet ◽  
Mohammed El Borai ◽  
Roger Guilard ◽  
Yves Dusausoy
Keyword(s):  
Double Bond ◽  
Bond Cleavage ◽  
Carbon Double Bond

Raman Spectra of Polyisoprene Rubbers

1970 ◽  
Vol 43 (2) ◽  
pp. 313-321 ◽  
Author(s):  
S. W. Cornell ◽  
J. L. Koenig
Keyword(s):  
Double Bond ◽  
Raman Spectra ◽  
Structure Type ◽  
Peak Height ◽  
Mixed Structure ◽  
Carbon Double Bond

Abstract The Raman spectra of cis-1,4-, trans-1,4-, and 3,4-polyisoprene are presented, and the frequencies are classified by configurational structure type. The stretching frequency of the carbon-carbon double bond vibrations are used to describe structure content. Only Raman bands characteristic of total 1,4 content and total vinyl content can be observed. Tentative values of structure content determined by both peak height and peak area are presented for two mixed structure rubbers.

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