Synthesis and transannular Diels–Alder reaction of a 13-membered macrocyclic triene having a tetrasubstituted enol ether as dienophile

1990 ◽  
Vol 68 (3) ◽  
pp. 404-411 ◽  
Author(s):  
Gervais Bérubé ◽  
Pierre Deslongchamps
Keyword(s):  
Organic Synthesis ◽  
Alder Reaction ◽  
Diels Alder ◽  
The Other ◽  
Enol Ether ◽  
Diels Alder Reaction ◽  
Other Hand ◽  
Tricyclic Compounds

The syntheses of the acyclic triene trans–trans–cis27 and trans–trans–trans31 are described. Macrocyclization and concomitant transannular Diels–Alder reaction were performed with the chloride derivative obtained from the trans–trans–cis triene alcohol 27 yielding a mixture of the tricyclic compounds trans–syn–trans33 and cis–syn–cis34. On the other hand, macrocyclization of the chloride derived from trans–trans–trans triene 31 was not successful. Keywords: transannular process, Diels–Alder reaction, macrocyclic triene, macrocyclization, tricyclic compounds, organic synthesis.

Preparation and Properties of Rubberlike High Polymers. II. Polymerization of Mixtures in Bulk

1947 ◽  
Vol 20 (2) ◽  
pp. 380-391
Author(s):  
C. Koningsberger ◽  
G. Salomon
Keyword(s):  
Mechanical Properties ◽  
Alder Reaction ◽  
Diels Alder ◽  
The Other ◽  
New Class ◽  
Diels Alder Reaction ◽  
Vinyl Compound ◽  
Other Hand ◽  
Higher Temperature ◽  
High Polymers

Abstract Mixtures of butadiene and dimethylbutadiene with varying quantities of styrene and acrylonitrile were copolymerized under various catalytic conditions at 100° C. The formation of cyclic dimers from dienes and vinyl compounds is, in some cases, much more pronounced than the dimerization of the dienes alone. Since the latter is also a kind of Diels-Alder reaction, a series with increasing dienophilic properties can be established from a comparison of the yields of cyclic dimers. From solubility and swelling experiments it is evident that the polymers prepared from butadiene and the vinyl compounds and those from dimethylbutadiene and acrylonitrile are true copolymers. The mechanical properties of the copolymers from butadiene and increasing amounts of a vinyl compound change gradually from those of a rubber to those of the polyvinyl compound. The copolymers from a mixture containing 30 per cent styrene or acrylonitrile are very similar to Buna-S and Perbunan, respectively. Copolymers of the same composition from dimethylbutadiene and acrylonitrile, on the other hand, form a new class of thermoplastics with a much higher temperature of elasticity.

Stereocontrolled construction of A.B.C.[6.6.6] tricycle via transannular Diels–Alder reaction of 14-membered macrocycle with acetylene as dienophile

1990 ◽  
Vol 68 (12) ◽  
pp. 2137-2143 ◽  
Author(s):  
Yao-Chang Xu ◽  
Michel Cantin ◽  
Pierre Deslongchamps
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
The Other ◽  
One Pot ◽  
Diels Alder Reaction ◽  
Other Hand ◽  
Tricyclic Compound ◽  
Stereocontrolled Synthesis ◽  
Allylic Chloride

The syntheses of the acyclic dienynes 14a (cis-trans-acetylene) and 14b (trans-trans-acetylene) are described. The tandem macrocyclization and transannular Diels–Alder reaction of the allylic chloride 14b was conducted in the presence of Cs2CO3 at 85 °C in one-pot to provide tricyclic product 16, with the two hydrogens in ring B being cis. On the other hand, treatment of the allylic chloride 14a under the same conditions afforded 14-membered macrocycle 17, which could be transformed at 250 °C into a similar tricyclic product 18 with the two hydrogens in ring B being trans, along with an interesting by-product 19. The mechanism for the formation of 19 is also discussed. Keywords: stereocontrolled synthesis, macrocycle, tricyclic compound, transannular Diels–Alder reaction.

Enantioselective Syntheses of Flavonoid Diels-Alder Natural Products: A Review

2018 ◽  
Vol 15 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Shah Bakhtiar Nasir ◽  
Noorsaadah Abd Rahman ◽  
Chin Fei Chee
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Lewis Acid ◽  
Alder Reaction ◽  
Diels Alder ◽  
Enantioselective Synthesis ◽  
Chiral Ligand ◽  
Asymmetric Syntheses ◽  
Diels Alder Reaction ◽  
Enantioselective Syntheses

Background: The Diels-Alder reaction has been widely utilised in the syntheses of biologically important natural products over the years and continues to greatly impact modern synthetic methodology. Recent discovery of chiral organocatalysts, auxiliaries and ligands in organic synthesis has paved the way for their application in Diels-Alder chemistry with the goal to improve efficiency as well as stereochemistry. Objective: The review focuses on asymmetric syntheses of flavonoid Diels-Alder natural products that utilize chiral ligand-Lewis acid complexes through various illustrative examples. Conclusion: It is clear from the review that a significant amount of research has been done investigating various types of catalysts and chiral ligand-Lewis acid complexes for the enantioselective synthesis of flavonoid Diels-Alder natural products. The results have demonstrated improved yield and enantioselectivity. Much emphasis has been placed on the synthesis but important mechanistic work aimed at understanding the enantioselectivity has also been discussed.

Sign in / Sign up

Export Citation Format

Share Document