scholarly journals Synthesis of the AB ring system of clifednamide utilizing Claisen rearrangement and Diels–Alder reaction as key steps

2016 ◽  
Vol 14 (3) ◽  
pp. 884-894 ◽  
Author(s):  
Inga Loke ◽  
Guillaume Bentzinger ◽  
Julia Holz ◽  
Aruna Raja ◽  
Aman Bhasin ◽  
...  
Keyword(s):  
Claisen Rearrangement ◽  
Alder Reaction ◽  
Ring System ◽  
Diels Alder ◽  
Tetramic Acid ◽  
Diels Alder Reaction ◽  
Key Steps ◽  
Ab Ring

A synthesis to the functionalized AB ring system of clifednamide, member of macrocyclic tetramic acid lactams, was developed involving an Ireland–Claisen rearrangement and an intramolecular Diels–Alder reaction.

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.

scholarly journals Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

2018 ◽  
Vol 14 ◽  
pp. 2468-2481 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Milind Meshram ◽  
Chandravathi Chakkapalli
Keyword(s):  
Recent Work ◽  
Claisen Rearrangement ◽  
Cross Coupling ◽  
Alder Reaction ◽  
Diels Alder ◽  
Enyne Metathesis ◽  
Cross Metathesis ◽  
Diels Alder Reaction ◽  
Synergistic Approach ◽  
Key Steps

This account provides an overview of recent work, including our own contribution dealing with Suzuki–Miyaura cross coupling in combination with metathesis (or vice-versa). Several cyclophanes, polycycles, macrocycles, spirocycles, stilbenes, biaryls, and heterocycles have been synthesized by employing a combination of Suzuki cross-coupling and metathesis. Various popular reactions such as Diels–Alder reaction, Claisen rearrangement, cross-metathesis, and cross-enyne metathesis are used. The synergistic combination of these powerful reactions is found to be useful for the construction of complex targets and fulfill synthetic brevity.

Domino Wittig Diels–Alder reaction: an expeditious entry into the AB ring system of furanosesquiterpenes

2007 ◽  
Vol 48 (20) ◽  
pp. 3517-3520 ◽  
Author(s):  
Rupesh E. Patre ◽  
Suraj Gawas ◽  
Saikat Sen ◽  
P.S. Parameswaran ◽  
Santosh G. Tilve
Keyword(s):  
Alder Reaction ◽  
Ring System ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Ab Ring

scholarly journals Crystal structures and conformations of two Diels–Alder adduct derivatives: 1,8-bis(thiophen-2-yl)-14-oxatetracyclo[6.5.1.02,7.09,13]tetradeca-2(7),3,5-trien-10-one and 1,8-diphenyl-14-oxatetracyclo[6.5.1.02,7.09,13] tetradeca-2,4,6-trien-10-one

2015 ◽  
Vol 71 (2) ◽  
pp. 213-216
Author(s):  
S. Gopinath ◽  
P. Narayanan ◽  
K. Sethusankar ◽  
Meganathan Nandakumar ◽  
Arasambattu K. Mohanakrishnan
Keyword(s):  
Crystal Packing ◽  
Rotation Axis ◽  
Alder Reaction ◽  
Ring System ◽  
Diels Alder ◽  
Compound I ◽  
Diels Alder Reaction ◽  
Phenyl Rings ◽  
Axis Parallel ◽  
Alder Adduct

The title compounds, C21H16O2S2(I) and C25H20O2(II), are products of a tandem `pincer' Diels–Alder reaction consisting of [2 + 2] cycloadditions between benzo[c]furan and cyclopentanone. Each comprises a fused tetracyclic ring system containing two five-membered rings (inenvelopeconformations with the O atom as the flap) and six-membered rings (inboatconformations). In addition, two thiophene rings in (I) and two phenyl rings in (II) are attached to the tetracyclic ring system. The cyclopentanone ring adopts atwistedconformation in (I) and anenvelopeconformation in (II). In (I), the thiophene rings are positionally disordered over two sets of sites, with occupancy ratios of 0.901 (2):0.099 (2) and 0.666 (2):0.334 (2). In (II), the oxygen atom of the cyclopentanone ring is rotationally disordered over two sites with an occupancy ratio of 0.579 (4):0.421 (4). The molecular structure of (I) is stabilized by an intramolecular C—H...O hydrogen bond, which generates anS(7) ring motif. In the crystal, the molecules are linkedviaweak C—H...O hydrogen bonds, which generateR22(16) ring motifs in (I) andC(8) chains in (II). In both structures, the crystal packing also features C—H...π interactions. The crystal studied of compound (I) was twinned by non-merohedry. The twin component is related by the twin law [−1 0 0 −0.101 1 −0.484 0 0 −1] operated by a twofold rotation axis parallel to thebaxis. The structure of (I) was refined with a twin scale factor of 0.275 (2).

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.

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