Hetero-Diels-Alder Reactions of 2H-Phospholes with Allenes: Synthesis and Functionalization of 6-Methylene-1-phosphanorbornenes

2021 ◽  
Author(s):  
Keke Zhang ◽  
Qiao-Yu Zhang ◽  
Donghui Wei ◽  
Rongqiang Tian ◽  
Zheng Duan
Keyword(s):  
Double Bond ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Reaction Proceeds ◽  
High Yields

The phospha-Diels–Alder reaction between 2H-phospholes and arylallenes afford 6-methylene-1-phosphanorbornenes in high yields and excellent regioselectivity. This Diels–Alder reaction proceeds at the internal C=C double bond of allenes selectively. The DFT...

A synthesis and some reactions of 7-Oxabicyclo[2.2.1]heptan-2-one

1983 ◽  
Vol 36 (12) ◽  
pp. 2473 ◽  
Author(s):  
J Moursounidis ◽  
D Wege
Keyword(s):  
Thermal Decomposition ◽  
Alder Reaction ◽  
Diels Alder ◽  
Acid Mixture ◽  
Diels Alder Reaction ◽  
Reaction Proceeds ◽  
Atom Migration ◽  
Acyl Azide ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

Diels-Alder reaction between furan and α-chloroacrylonitrile gives a mixture of exo-2-chloro-and endo-2-chloro-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitrile (4) and (5). Mild hydrolysis affords the corresponding α-chloro acid mixture, from which the endo carboxylic acid may be removed through iodo lactone formation. Catalytic hydrogenation of (4) and (5) followed by hydrolysis, acyl azide formation, Curtius rearrangement, and hydrolysis of the resulting mixture of a-chloro isocyanates yields 7-oxabicyclo[2.2.l]heptan-2-one (1) in preparatively useful amounts. Reduction of (1) gives only endo alcohol, and Baeyer-Villiger reaction proceeds with exclusive bridgehead atom migration. Thermal decomposition of the sodium salt of the p-toluenesulfonylhydrazone of (1) affords 7-oxatricyclo[2.2.1 .02,6]heptane.

Synthesis and Application of Tetrafluoroethylene (CF2CF2)-Containing Acetylene Derivatives

Synthesis ◽  
2020 ◽  
Vol 52 (13) ◽  
pp. 1947-1958
Author(s):  
Tsutomu Konno ◽  
Gen Egashira ◽  
Chihiro Kajimoto ◽  
Takuto Kataoka ◽  
Shigeyuki Yamada
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Alder Reaction ◽  
Diels Alder ◽  
Benzene Derivatives ◽  
Diels Alder Reaction ◽  
Cross Coupling Reaction ◽  
Oxidative Aromatization ◽  
High Yields ◽  
Acetylene Derivatives

On treating 1,3,4-tribromo-1,1,2,2-tetrafluorobutane, readily prepared from commercially available 4-bromo-3,3,4,4-tetrafluorobut-1-ene, with 3.3 equivalents of LHMDS at 0 °C in THF, the corresponding lithium acetylide could be prepared quantitatively. The acetylide reacted well with various aldehydes, ketones, or chlorosilanes to give the corresponding acetylene derivatives in high yields. It was also found that various iodoarenes could participate in the cross-coupling reaction with the zinc acetylide, readily prepared from the lithium acetylide and ZnCl2·TMEDA complex, in the presence of Pd(PPh3)4 to bring about the adducts in high yields. Thus-obtained acetylene derivatives underwent smooth Diels–Alder reaction with various 1,3-dienes to afford the corresponding 1,4- or 1,3-cyclohexadiene derivatives. In addition, it was revealed that the oxidative aromatization of the resulting cyclohexadiene derivatives with DDQ took place very smoothly, providing the multi-substituted benzene derivatives having a tetrafluoro­ethylene group.

Exploratory synthetic investigations related to 12a-deoxypillaromycinone

2002 ◽  
Vol 80 (6) ◽  
pp. 728-738 ◽  
Author(s):  
Lan Wang ◽  
Sanath K Meegalla ◽  
Cheng-Lin Fang ◽  
Nicholas Taylor ◽  
Russell Rodrigo
Keyword(s):  
Double Bond ◽  
Catalytic Hydrogenation ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Step Procedure ◽  
Key Steps

Furfural is converted to suitably substituted AB synthon 21 for 12a-deoxypillaromycinone in 10 steps by a sequence involving the following key steps: intramolecular Diels-Alder reaction of a furan, 5-endo-trig cleavage of the oxabicyclo adducts 18, and catalytic hydrogenation of the double bond of a tetrasubstituted enone to produce 19. Enones 21a and 21b obtained by dehydrogenation of 19a and 19b, respectively, are then annulated with ethyl 2-methoxy-6-methylbenzoate in a four-step procedure to generate tetracyclic products 25 in 14 steps from furfural.

Copper(i)/TF-BiphamPhos catalyzed asymmetric nitroso Diels–Alder reaction

2017 ◽  
Vol 53 (10) ◽  
pp. 1657-1659 ◽  
Author(s):  
Jun Li ◽  
Hai-Yan Tao ◽  
Chun-Jiang Wang
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Highly Efficient ◽  
Diels Alder Reaction ◽  
Cyclic Dienes ◽  
High Yields

A highly efficient enantioselective nitroso Diels–Alder reaction of 6-methyl-2-nitroso pyridine with various 1,3-dienes was successfully developed using a copper(i)/(S)–TF-BiphamPhos complex as the catalyst. For most of the cyclic dienes, the cycloadducts were obtained in high yields with excellent regio-, and stereoselectivities. Acyclic 2-silyloxy-1,3-diene also worked well in the reaction.

Diels-Alder Reaction Curing of Chlorobutyl Rubber by bis-Maleimides

1989 ◽  
Vol 62 (1) ◽  
pp. 42-54 ◽  
Author(s):  
K. Ho ◽  
R. Steevensz
Keyword(s):  
Zinc Oxide ◽  
Double Bond ◽  
Chain Length ◽  
Crosslinking Agent ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Electronic Distribution ◽  
Curing Agents ◽  
Chlorobutyl Rubber

Abstract Different bis-maleimides are found to have different efficiencies and reactivities in the crosslinking of CIIR in the presence of zinc oxide. Although the degrees of crosslinking of CIIR by bis-maleimides cannot be defined absolutely, some trends concerning the efficiencies of the crosslinking are evident. In general, the aromatic bis-maleimides gave higher degrees of crosslinking than the aliphatic analogs. The reactivity and crosslinking efficiency of an individual bis-maleimide is very much affected by its end-to-end chain length and its electronic distribution, resulting from the interaction between the maleimide groups, and from the interaction between the maleimide groups and other functional groups present in the same molecule. The longer the bis-maleimide molecule and the more electron deficient the maleimido double bond, the greater its effectiveness as a crosslinking agent. Other curing mechanisms, possibly including polymerization of the maleimido groups, appear to be operative when using aromatic bis-maleimides as curing agents for CIIR.

scholarly journals Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

2021 ◽  
Vol 17 ◽  
pp. 719-729
Author(s):  
Ramazan Koçak ◽  
Arif Daştan
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Reductive Treatment ◽  
High Yields ◽  
Derivatives Of ◽  
Electron Demand

The synthesis of novel polycyclic π-conjugated dihydropyridazines, pyridazines, and pyrroles was studied. Dihydropyridazine dyes were synthesized by inverse electron-demand Diels–Alder cycloaddition reactions between a dibenzosuberenone and tetrazines that bear various substituents. The pyridazines were synthesized in high yields by oxidation of dihydropyridazine-appended dibenzosuberenones with PIFA or NO. p-Quinone derivatives of pyridazines were also obtained by H-shift isomerization following the inverse electron-demand Diels–Alder reaction of tetrazines with p-quinone dibenzosuberenone. Then these pyridazines were converted to the corresponding pyrroles by reductive treatment with zinc. It was observed that all the dihydropyridazines obtained gave absorbance and emission at long wavelengths.

scholarly journals TiCl3 as a New Catalyst for the Imino Diels-Alder Reaction

2006 ◽  
Vol 1 (9) ◽  
pp. 1934578X0600100
Author(s):  
Narayan V. Mayekar ◽  
Sandip K. Nayak ◽  
Subrata Chattopadhyay
Keyword(s):  
Ambient Temperature ◽  
Alder Reaction ◽  
Diels Alder ◽  
Trans Isomers ◽  
Effective Catalyst ◽  
Diels Alder Reaction ◽  
Cis And Trans Isomers ◽  
Reaction Proceeds ◽  
Cis And Trans

Titanium(III) chloride was found to be an effective catalyst for the imino Diels-Alder reaction between an imine (generated in situ) and an activated alkene in acetonitrile at ambient temperature. The reaction proceeds smoothly to afford the corresponding adduct as a mixture of chromatographically separable cis- and trans isomers in moderate to good yields.

Multiple Activation Catalyst for Asymmetric [4+2] Cycloaddition of Aldehydes with Dienes

Synlett ◽  
2021 ◽  
Author(s):  
Takuya Kurahashi ◽  
Seijiro Matsubara ◽  
Rei Tomifuji ◽  
Shunpei Murano ◽  
Satoru Teranishi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Addition Reaction ◽  
Catalyst System ◽  
Alder Reaction ◽  
Diels Alder ◽  
Functional Theory ◽  
Diels Alder Reaction ◽  
Chiral Phosphoric Acid ◽  
High Yields

AbstractThe enantioselective oxa-Diels–Alder reaction of nonactivated substrates by utilizing FeCl3 and a 1,1′-bi-2-naphthol (BINOL) derived chiral phosphoric acid as a multiple activation catalyst is reported. Various oxygen-containing six-membered heterocycles were obtained in high yields and in an enantioselective manner. Density functional theory (DFT) calculations elucidate that both Lewis acidic and Brønsted acidic moieties in the catalyst system synergistically activate two lone pairs of an aldehyde to facilitate enantioselective addition reaction of dienes.

Sign in / Sign up

Export Citation Format

Share Document