Studies on the transannular Diels–Alder reaction of 15-membered macrocyclic trienes containing a trans-trans diene. Part II: Evidence for unsymmetrical transition states in the formation of A.B.C.[6.6.7] tricyclic products

1995 ◽  
Vol 73 (10) ◽  
pp. 1695-1710 ◽  
Author(s):  
Dennis G. Hall ◽  
Renate Müller ◽  
Pierre Deslongchamps
Keyword(s):  
Lewis Acids ◽  
Transition States ◽  
Preceding Paper ◽  
Alder Reaction ◽  
Membered Ring ◽  
Diels Alder ◽  
Proximity Effects ◽  
Diels Alder Reaction ◽  
Stereocontrolled Synthesis ◽  
First Time

In the preceding paper (Part I) we described the preparation of 10 model TTT and TTC cyclopentadecatrienes. Their conversion to A.B.C.[6.6.7] tricyclic products via a transannular Diels–Alder (TADA) reaction and the analysis of the resulting diastereoselection along with proofs of structures are described in the present article (Part II). The required temperature of reaction was significantly higher (~100 °C) in comparison to that required for the 14-membered lower homologs, indicating that proximity effects are playing a key role in the TADA reaction. The presence of ester groups in the chain was found to favor either of the two possible transition states (endo or exo) on the basis of steric effects, thus controlling the TST/CSC ratio of tricycles from TTC macrocycles, and the TAC/CAT ratio from TTT macrocycles. A formyl substituent on the dienophile can further influence the diastereoselection through the hypothesis of unsymmetrical transition states and allowed, for the first time, the use of Lewis acids as catalysts in the TADA reaction. This investigation demonstrates a general methodology for the stereocontrolled synthesis of A.B.C.[6.6.7] tricycle structures related to several polycyclic natural products. Keywords: transannular, Diels–Alder, 15-membered ring, A.B.C.[6.6.7] tricycles, diterpene.

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.

Influence of Lewis Acids on the Diels–Alder Reaction. IV. Reaction of 2-Methyl- and 2-Phenylfuran with Ethyl Propiolate

1971 ◽  
Vol 49 (19) ◽  
pp. 3152-3157 ◽  
Author(s):  
A. W. Mcculloch ◽  
A. G. McInnes
Keyword(s):  
Methyl Acrylate ◽  
Lewis Acids ◽  
Alder Reaction ◽  
Diels Alder ◽  
Methyl Propionate ◽  
Diels Alder Reaction ◽  
By Products

The AlCl3-promoted reactions of 2-methyl- and of 2-phenylfuran with ethyl propiolate afford as major products ethyl 5-hydroxy-2-methyl- and 2-phenylbenzoates (6a, 6b). Also isolated as minor by-products of these reactions are ethyl 3-(2-furyl-5-methyl)acrylate (5a), ethyl 3-(2-furyl-5-phenyl)acrylate (5b), ethyl 3,3-di(2-furyl-5-methyl)propionate (10a), ethyl 3,3-di(2-furyl-5-phenyl)propionate (10b), and ethyl 2-hydroxy-5-methylbenzoate (8a).

Stereo-controlled synthesis of polyheterocycles via the diene-transmissive hetero-Diels–Alder reaction of β,γ-unsaturated α-keto esters

2015 ◽  
Vol 13 (21) ◽  
pp. 5875-5879 ◽  
Author(s):  
Takashi Otani ◽  
Yumiko Tamai ◽  
Kazunori Seki ◽  
Tomohiro Kikuchi ◽  
Taiichiro Miyazawa ◽  
...  
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Controlled Synthesis ◽  
Keto Esters ◽  
Diels Alder Reaction ◽  
Stereocontrolled Synthesis

Stereocontrolled synthesis of polyheterocycles via the diene-transmissive hetero Diels–Alder reaction of β,χ-unsaturated α-keto esters is described.

Ring-Closing Metathesis Approach to Cage Propellanes Containing Oxepane and Tetrahydrofuran Hybrid System

Synthesis ◽  
2017 ◽  
Vol 49 (24) ◽  
pp. 5339-5350 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Subba Cheekatla ◽  
Darshan Mhatre
Keyword(s):  
Claisen Rearrangement ◽  
Alder Reaction ◽  
Diels Alder ◽  
Ring Closing Metathesis ◽  
Cage Compounds ◽  
Transannular Cyclization ◽  
Diels Alder Reaction ◽  
Grignard Addition ◽  
Key Steps ◽  
First Time

The preparation of a variety of structurally interesting oxygenated cage compounds involving atom-economic processes such as Claisen rearrangement, Diels–Alder reaction, [2+2] photocycloaddition, and ring-closing metathesis (RCM) as key steps is reported. For the first time, oxepane ring system is introduced in cage framework using olefin metathesis as a key step. These cage systems assembled here are difficult to prepare by traditional methods. The synthetic sequence described here opens up new routes to higher order polycycles containing heteroatoms without the involvement of protecting groups. Transannular cyclization observed during Grignard addition and the RCM protocol used here may be applicable to generate unknown oxygenated cage systems.

An examination of VANOL, VAPOL, and VAPOL derivatives as ligands for asymmetric catalytic Diels–Alder reactions

2006 ◽  
Vol 84 (10) ◽  
pp. 1487-1503 ◽  
Author(s):  
Douglas P Heller ◽  
Daniel R Goldberg ◽  
Hongqiao Wu ◽  
William D Wulff
Keyword(s):  
Asymmetric Catalysis ◽  
Methyl Acrylate ◽  
Lewis Acids ◽  
Alder Reaction ◽  
Diels Alder ◽  
Asymmetric Catalytic ◽  
Diels Alder Reaction ◽  
Positive Cooperativity ◽  
Derivatives Of ◽  
Methyl Phenyl

Several derivatives of the vaulted biaryl ligand VAPOL were prepared and evaluated as chiral ligands for aluminum Lewis acids in the catalytic asymmetric Diels–Alder reactions of methyl acrylate and methacrolein with cyclopentadiene. The substituents on VAPOL were introduced into the 6- and 6′-positions in an effort to further extend the chiral pocket of the major groove, which contains the phenol functions at the 4- and 4′-positions. The set of four new ligands that have been prepared have the following groups introduced into the 6- and 6′-positions of VAPOL: bromide, methyl, phenyl and 3,5-di-t-butylphenyl. All of these ligands give lower asymmetric inductions than the unsubstituted VAPOL for the Diels–Alder reactions of both methyl acrylate and methacrolein. The positive cooperativity of added carbonyl compounds on the autoinduction in the Diels–Alder reaction of methyl acrylate and cyclopentadiene were also investigated with the VANOL and VAPOL ligands as well as the 6,6′-dibromo and 6,6′-diphenyl derivatives of VAPOL. Only the reaction with VAPOL showed any significant positive cooperativity. The reaction with VANOL was sluggish at –78 °C, but at higher temperatures, the reaction did exhibit positive cooperativity that was similar to that of VAPOL. Finally, no positive cooperativity was observed with the VAPOL ligand for the reaction of methacrolein and cyclopentadiene.Key words: Diels–Alder, asymmetric catalysis, vaulted biaryl ligands, VANOL, VAPOL.

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.

Influence of Lewis acids on the Diels–Alder reaction. III. Rearrangement of dimethyl N-carbomethoxy-7-azabicyclo[2.2.1]2,5-heptadiene-2,3-dicarboxylate adducts to dimethyl N-carbomethoxy-3-aminophthalates

1970 ◽  
Vol 48 (9) ◽  
pp. 1472-1474 ◽  
Author(s):  
R. C. Bansal ◽  
A. W. McCulloch ◽  
A. G. McInnes
Keyword(s):  
Aluminum Chloride ◽  
Lewis Acids ◽  
Alder Reaction ◽  
Diels Alder ◽  
Prolonged Treatment ◽  
Dimethyl Acetylenedicarboxylate ◽  
Diels Alder Reaction ◽  
Convenient Route

Aluminum chloride accelerates the Diels–Alder reactions of 2- or 2,5-substituted N-carbomethoxypyrroles with dimethyl acetylenedicarboxylate, and also catalyzes rearrangement of the N-carbomethoxy-7-azanorbornadiene adducts to 6- and 4,6-substituted dimethyl N-carbomethoxy-3-aminophthalates. Aromatization of the corresponding adduct of N-carbomethoxypyrrole only occurs on prolonged treatment with BF3. The procedure promises to be a convenient route for the synthesis of polysubstituted anilines.

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