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 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.

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).

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