scholarly journals A rhodium catalyzed cycloisomerization and tandem Diels–Alder reaction for facile access to diverse bicyclic and tricyclic heterocycles

2019 ◽  
Vol 10 (18) ◽  
pp. 4805-4810 ◽  
Author(s):  
Yirong Zhou ◽  
Ali Nikbakht ◽  
Felix Bauer ◽  
Bernhard Breit
Keyword(s):  
Alder Reaction ◽  
Membered Ring ◽  
Diels Alder ◽  
Catalyst Loading ◽  
Diels Alder Reaction ◽  
Low Catalyst Loading

A rhodium catalyzed cycloisomerization of 1,6-allenenes successfully prepared six-membered ring exocyclic 1,3-dienes. Further tandem Diels–Alder reaction with various dienophiles provided diverse bicyclic and tricyclic heterocycles. This methodology is characterised by complete atom and step economy, low catalyst loading, and excellent chemo-, regio-, and diastereoselectivity.

scholarly journals Asymmetric Organocatalysis Revisited: Taming Hydrindanes with Jørgensen–Hayashi Catalyst

Synthesis ◽  
2018 ◽  
Vol 51 (05) ◽  
pp. 1123-1134 ◽  
Author(s):  
Yannick Stöckl ◽  
Wolfgang Frey ◽  
Johannes Lang ◽  
Birgit Claasen ◽  
Angelika Baro ◽  
...  
Keyword(s):  
Aldol Condensation ◽  
Alder Reaction ◽  
Diels Alder ◽  
Catalyst Loading ◽  
Diels Alder Reaction ◽  
Stereogenic Centers ◽  
Asymmetric Organocatalysis ◽  
Molecular Complexity ◽  
Low Catalyst Loading ◽  
High Degree

The organocatalytic Michael reaction of easily available 1-cyclopentene-1-carbaldehyde and 1,3-dicarbonyl compounds led to cyclopentanecarbaldehydes on a gram scale with low catalyst loading (2 mol%) and high enantioselectivity. The synthetic potential of 4-acylhexahydroindenones from intramolecular aldol condensation was demonstrated by Diels–Alder reaction to a tetracyclic derivative with seven stereogenic centers. The diastereofacial preference of the tetracyclic product was confirmed by DFT calculations. The described reaction sequence is characterized by few redox-economic steps and high degree of molecular complexity.

scholarly journals Studies on the transannular Diels–Alder reaction of 15-membered macrocyclic trienes containing a trans-trans diene. Part I: Synthesis and isomerization of various model cyclopentadecatrienes

1995 ◽  
Vol 73 (10) ◽  
pp. 1675-1694 ◽  
Author(s):  
Dennis G. Hall ◽  
Renate Müller ◽  
Pierre Deslongchamps
Keyword(s):  
Aqueous Media ◽  
Alder Reaction ◽  
Membered Ring ◽  
Diels Alder ◽  
Coupling Reactions ◽  
Diels Alder Reaction ◽  
Trans Diene

The transannular Diels–Alder reaction of 15-membered macrocyclic trienes with a trans-trans-cis (TTC) olefin geometry can lead to A.B.C.[6.6.7] tricyclic products of trans-syn-trans (TST) and cis-syn-cis (CSC) stereochemistry whereas the TTT isomers can produce the trans-anti-cis (TAC) and cis-anti-trans (CAT) tricycles. In order to study the influence of the position (pro-6.6 or pro-6.7) and the nature (alkyl, alkoxymethyl, or formyl) of the dienophile substituent, a set of 10 model cyclopentadecatrienes was prepared. The synthesis of appropriately functionalized trisubstituted dienophile and diene synthons, as well as their coupling reactions affording acyclic precursors, is described in this paper (first in a series of two). A mild and efficient macrocyclization protocol yielded the required methyl- or alkoxymethyl-substituted cyclic substrates. Further transformations led to the formyl-substituted ones. In particular, the TTT macrocycles containing an enal as a dienophile could be completely isomerized to the corresponding TTC thermodynamic isomers in acidic aqueous media. Keywords: transannular, Diels–Alder, 15-membered ring, A.B.C.[6.6.7] tricycles, diterpene.

Activated cycloheptenone dienophiles. A versatile approach to 6,7-fused ring targets

1995 ◽  
Vol 73 (7) ◽  
pp. 1135-1147 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Wen-Lung Yeh ◽  
Eric N.C. Browne
Keyword(s):  
Natural Products ◽  
Alder Reaction ◽  
Ring System ◽  
Membered Ring ◽  
Diels Alder ◽  
Substitution Pattern ◽  
Diels Alder Reaction ◽  
Fused Ring ◽  
Fused Ring System

Several 2-carbalkoxy-2-cyclohepten-1-ones were prepared and their Diels–Alder characteristics examined in order to develop a facile general approach to the synthesis of cycloheptane ring-containing polycyclic natural products. Substitution pattern on the seven-membered ring was found to greatly affect the Diels–Alder behavior. In addition, some extraordinary facial stereoselectivity was observed. Keywords: Diels–Alder reaction, 2-carbalkoxy-2-cyclohepten-1-ones, 6,7-fused ring system.

The First Halogen-Substituted Cyclotrigermenes:  A Unique Halogen Walk over the Three-Membered Ring Skeleton and Facial Stereoselectivity in the Diels−Alder Reaction

2002 ◽  
Vol 124 (7) ◽  
pp. 1158-1159 ◽  
Author(s):  
Akira Sekiguchi ◽  
Yutaka Ishida ◽  
Norihisa Fukaya ◽  
Masaaki Ichinohe ◽  
Nozomi Takagi ◽  
...  
Keyword(s):  
Alder Reaction ◽  
Membered Ring ◽  
Diels Alder ◽  
Diels Alder Reaction

scholarly journals Studies towards the Synthesis of the Antibiotic Tetrodecamycin

Synlett ◽  
2018 ◽  
Vol 29 (08) ◽  
pp. 1117-1121
Author(s):  
Victor Lee ◽  
Jing He ◽  
Jack Baldwin
Keyword(s):  
Natural Product ◽  
Wittig Reaction ◽  
Alder Reaction ◽  
Membered Ring ◽  
Diels Alder ◽  
Acid Moiety ◽  
Tetronic Acid ◽  
Diels Alder Reaction

A study towards the natural product tetrodecamycin is reported. A modified Schlosser–Wittig reaction was utilized to prepare the precursor for the subsequent intramolecular Diels–Alder reaction, which delivered the trans-decalin ring of the natural product. The tetronic­ acid moiety of the molecule was prepared by a Dieckmann cyclization­. The cyclization of the tetronic acid to the trans-decalin double­ bond to form a seven-membered ring was examined.

scholarly journals Application of New Efficient Hoveyda–Grubbs Catalysts Comprising an N→Ru Coordinate Bond in a Six-Membered Ring for the Synthesis of Natural Product-Like Cyclopenta[b]furo[2,3-c]pyrroles

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5379
Author(s):  
Alexandra S. Antonova ◽  
Marina A. Vinokurova ◽  
Pavel A. Kumandin ◽  
Natalia L. Merkulova ◽  
Anna A. Sinelshchikova ◽  
...  
Keyword(s):  
Maleic Anhydride ◽  
Natural Product ◽  
Alder Reaction ◽  
Membered Ring ◽  
Diels Alder ◽  
New Class ◽  
Diels Alder Reaction ◽  
Grubbs Catalysts ◽  
Coordinate Bond ◽  
Diastereomer Mixture

The ring rearrangement metathesis (RRM) of a trans-cis diastereomer mixture of methyl 3-allyl-3a,6-epoxyisoindole-7-carboxylates derived from cheap, accessible and renewable furan-based precursors in the presence of a new class of Hoveyda–Grubbs-type catalysts, comprising an N→Ru coordinate bond in a six-membered ring, results in the difficult-to-obtain natural product-like cyclopenta[b]furo[2,3-c]pyrroles. In this process, only one diastereomer with a trans-arrangement of the 3-allyl fragment relative to the 3a,6-epoxy bridge enters into the rearrangement, while the cis-isomers polymerize almost completely under the same conditions. The tested catalysts are active in the temperature range from 60 to 120 °C at a concentration of 0.5 mol % and provide better yields of the target tricycles compared to the most popular commercially available second-generation Hoveyda–Grubbs catalyst. The diastereoselectivity of the intramolecular Diels–Alder reaction furan (IMDAF) reaction between starting 1-(furan-2-yl)but-3-en-1-amines and maleic anhydride, leading to 3a,6-epoxyisoindole-7-carboxylates, was studied as well.

Heterocyclische Siebenring-Verbindungen, XXIX [1] Bildung und Abfangreaktionen von substituierten 2,3-Dehydro- 1,5-benzodioxepinen / Heterocyclic Seven-Membered Ring Compounds, XXIX [1] Formation and Trapping Reactions of Substituted 2,3-Dehydro-1,5-benzodioxepins

1985 ◽  
Vol 40 (11) ◽  
pp. 1575-1579 ◽  
Author(s):  
Hans Hofmann ◽  
Gerhard Löw ◽  
Armin Haag
Keyword(s):  
Alder Reaction ◽  
Membered Ring ◽  
Diels Alder ◽  
Ring Compounds ◽  
Diels Alder Reaction ◽  
Trapping Reactions

4-Cyano- and 4-Carbomethoxy-3,4-dihydro-2H-l,5-benzodioxepin-3-one (1a and 1b) have been converted to the corresponding enol-toluenesulfonates 2a and 2b, respectively. Reaction of 2a and 2b with base led to the heterocyclic allenes 3a resp. 3b, which could be trapped by Diels-Alder-reaction with furane, yielding the cycloadducts 4a and 4b.

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