ChemInform Abstract: Cycloaddition Reactions of 2- or 3-Substituted 1-Benzopyran-4-ones Having a Double Bond in Conjugation with the Pyran 2,3-Olefinic Bond

ChemInform ◽  
2012 ◽  
Vol 43 (6) ◽  
pp. no-no
Author(s):  
Chandra Kanta Ghosh
Keyword(s):  
Double Bond ◽  
Cycloaddition Reactions ◽  
Olefinic Bond ◽  
Substituted 1

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

Formation of Dihydroaza-azulanones Possessing Spirocyclic Moieties: [8+2] Type Cycloaddition Reactions of Iminotropones to an Exocyclic Double Bond of 8-Oxoheptafulvene

Heterocycles ◽  
1995 ◽  
Vol 41 (10) ◽  
pp. 2181 ◽  
Author(s):  
Katsuhiro Saito ◽  
Yuka Saito ◽  
Masayuki Tomita ◽  
Hiroshi Taniguchi ◽  
Hirofumi Okabayashi
Keyword(s):  
Double Bond ◽  
Exocyclic Double Bond ◽  
Cycloaddition Reactions

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.

Utilization of [2 + 1] Cycloaddition Reactions of 1-Seleno-2-silylethenes:  A Novel Synthesis of 2-Substituted 1-Aminocyclopropane-1-carboxylic Acids

1999 ◽  
Vol 64 (1) ◽  
pp. 282-286 ◽  
Author(s):  
Shoko Yamazaki ◽  
Takashi Inoue ◽  
Taro Hamada ◽  
Takashi Takada ◽  
Kagetoshi Yamamoto
Keyword(s):  
Carboxylic Acids ◽  
Cycloaddition Reactions ◽  
Novel Synthesis ◽  
Substituted 1

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
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