Facial selective Diels–Alder reactions of (1R,5R)-(+)-3-carbomethoxy-6,6-dimethylbicyclo[3.1.1]hept-3-en2-one. Unusual ketalization–fragmentation reaction of adducts

1994 ◽  
Vol 72 (5) ◽  
pp. 1193-1210 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Sew Yeu Chew ◽  
Eric N. C. Browne ◽  
Jeung Bea Kim
Keyword(s):  
High Selectivity ◽  
Alder Reaction ◽  
Diels Alder ◽  
Ambient Temperatures ◽  
Diels Alder Reaction ◽  
Unexpected Reaction ◽  
Catalyzed Reactions ◽  
High Yields ◽  
Cyclobutane Ring ◽  
Steric Influence

The stereofacially differentiated enone ester 5 has been used to study the effects of steric influence on the Diels–Alder reaction. In general, under Lewis acid catalysis, 5 adds to dienes at low to ambient temperatures in a reasonable rate. Yields of predictable chiral adducts are moderate with the unexpected exception of zinc chloride catalyzed reactions, which provide good to high yields. In all cases only products of addition to the Si face of general type 21 were observed. The regiochemistry of the adducts is exclusively that predicted by the ortho and para rules. The stereochemistry shows a high selectivity in favor of ester-endo transition state products. Rationales for the observed stereoselectivities are discussed. The fragmentation of adducts of 5, in particular keto ester 9, has been briefly examined. Olefins 30 and 46 derived from 9 have been converted to ring-opened cadinane skeletons 31 and 47, respectively, by conditions we have previously reported. In an entirely new and unexpected reaction, simultaneous ketalization and fragmentation of the cyclobutane ring of ketones derived from 9 gave ring-opened ketals 34 + 35 (from 29), 36 + 37 (from 9), 39 (from 38) and 42 + 43 (from 40).

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.

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.

scholarly journals Natural amino acids as chiral auxiliaries in asymmetric Diels–Alder reactions

1988 ◽  
Vol 66 (11) ◽  
pp. 2826-2829 ◽  
Author(s):  
Maria P. Bueno ◽  
Carlos Cativiela ◽  
José A. Mayoral ◽  
Alberto Avenoza ◽  
Paula Charro ◽  
...  
Keyword(s):  
Amino Acids ◽  
Structural Similarity ◽  
Alder Reaction ◽  
Diels Alder ◽  
Isopropyl Ester ◽  
Chiral Auxiliaries ◽  
Titanium Catalysts ◽  
Diels Alder Reaction ◽  
Catalyzed Reactions ◽  
Natural Amino Acids

To test whether α-amino acids can be efficient chiral auxiliaries in asymmetric Diels–Alder reactions, the chiral dienophile N-acryloyl-L-phenylalanine methyl ester was made to react with cyclopentadiene. Diastereofacial selectivity is to a great extent dependent on the Lewis acid used to promote the reaction; whereas moderate excesses of the (1R,2R)-cycloadduct were achieved with AlCl3, the reaction did not show diastereofacial selectivity when titanium catalysts were used. Moreover, with Ti(iPrO)4 a transesterification reaction, which leads to the isopropyl ester and competes with the Diels–Alder reaction, was observed. In spite of the structural similarity of this dienophile to the acrylate of (S)-ethyl lactate, it behaved very differently in the titanium-catalyzed reactions.

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.

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.

Diels–Alder Reactions of 1,2-Dihydropyridines: An Efficient Tool for the Synthesis of Isoquinuclidines

Synthesis ◽  
2018 ◽  
Vol 50 (09) ◽  
pp. 1773-1782 ◽  
Author(s):  
Eduarda Silva ◽  
Artur Silva ◽  
Djenisa Rocha
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Efficient Tool ◽  
Organometallic Catalysts ◽  
Diels Alder Reaction ◽  
Straightforward Method ◽  
Recent Developments ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Valuable Compounds

The Diels–Alder reaction of 1,2-dihydropyridines with different dienophiles is a well-established and straightforward method for the synthesis of isoquinuclidines. Nevertheless, the enantioselective preparation of isoquinuclidines using organocatalysts or organometallic catalysts is rather unexplored. This succinct review offers readers an overall perspective of the most important recent developments and concepts related to this topic.1 Introduction2 Asymmetric Diels–Alder Reaction of 1,2-Dihydropyridines2.1 Transition-Metal-Catalyzed Reactions2.2 Organocatalyzed Reactions3 Diels–Alder Reaction of 1,2-Dihydropyridines in the Synthesis of Biologically Valuable Compounds4 Conclusion

Total synthesis of the complex taxane diterpene canataxpropellane

Science ◽  
2020 ◽  
Vol 367 (6478) ◽  
pp. 676-681 ◽  
Author(s):  
Fabian Schneider ◽  
Konstantin Samarin ◽  
Simone Zanella ◽  
Tanja Gaich
Keyword(s):  
Total Synthesis ◽  
Anticancer Agent ◽  
Alder Reaction ◽  
Diels Alder ◽  
Core Structure ◽  
Natural Sources ◽  
The Core ◽  
Diels Alder Reaction ◽  
Cyclobutane Ring ◽  
Quaternary Carbons

Canataxpropellane belongs to the medicinally important taxane diterpene family. The most prominent congener, Taxol, is one of the most commonly used anticancer agent in clinics today. Canataxpropellane exhibits a taxane skeleton with three additional transannular C–C bonds, resulting in a total of six contiguous quaternary carbons, of which four are located on a cyclobutane ring. Unfortunately, isolation of canataxpropellane from natural sources is inefficient. Here, we report a total synthesis of (–)-canataxpropellane in 26 steps and 0.5% overall yield from a known intermediate corresponding to 29 steps from commercial material. The core structure of the (–)-canataxpropellane (2) was assembled in two steps using a Diels–Alder/ortho-alkene-arene photocycloaddition sequence. Enantioselectivity was introduced by designing chiral siloxanes to serve as auxiliaries in the Diels–Alder reaction.

Four-step one-pot catalytic asymmetric synthesis of multisubstituted tricyclic compounds: Lipase-catalyzed dynamic kinetic resolution followed by an intramolecular Diels–Alder reaction

Synlett ◽  
2021 ◽  
Author(s):  
Izuru Tsuchimochi ◽  
Shuhei Hori ◽  
Yasuo Takeuchi ◽  
Masahiro Egi ◽  
Tomo-o Satoh ◽  
...  
Keyword(s):  
Hydroxy Group ◽  
Kinetic Resolution ◽  
Alder Reaction ◽  
Diels Alder ◽  
One Pot ◽  
Diels Alder Reaction ◽  
Tricyclic Compounds ◽  
High Yields ◽  
Group Migration ◽  
Oxovanadium Compounds

Starting from readily available tertiary alcohols, four different reactions (i.e., a 1,3-migration of a hydroxy group, kinetic resolution, racemization, and an intramolecular Diels–Alder reaction) took place under the co-catalysis of lipase and oxovanadium compounds in a one-pot process to produce multisubstituted tricyclic carbon frameworks in high yields and high enantioselectivities. The key to the success of this process was the discovery that the silyl group attached to the terminal carbon of the vinyl moiety completely controls the direction of hydroxy group migration.

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