A common synthetic route to homochiral tetracycles related to pillaromycinone and premithramycinone

2011 ◽  
Vol 89 (12) ◽  
pp. 1457-1468 ◽  
Author(s):  
Bryan Hill ◽  
Robert Jordan ◽  
Yang Qu ◽  
Abdeljalil Assoud ◽  
Russell Rodrigo
Keyword(s):  
Double Bond ◽  
Alder Reaction ◽  
Diels Alder ◽  
Synthetic Route ◽  
Homogeneous Hydrogenation ◽  
Diels Alder Reaction

Homochiral AB segments for (+)- and (–)-pillaromycinone were prepared in 11 steps from 2-acetylfuran. The synthesis featured an intramolecular Diels–Alder reaction of a 2,5-disubstituted furan and a hydroxyl-directed homogeneous hydrogenation of the tetrasubstituted alkene double bond of two enones. The CD segment was attached by a modified Staunton–Weinreb annulation to produce the desired homochiral tetracycle 21c related to (+)-pillaromycinone. An unusual acetonide migration enabled the synthesis of a tetracyclic model for premithramycinone.

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.

Diels-Alder Reaction Curing of Chlorobutyl Rubber by bis-Maleimides

1989 ◽  
Vol 62 (1) ◽  
pp. 42-54 ◽  
Author(s):  
K. Ho ◽  
R. Steevensz
Keyword(s):  
Zinc Oxide ◽  
Double Bond ◽  
Chain Length ◽  
Crosslinking Agent ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Electronic Distribution ◽  
Curing Agents ◽  
Chlorobutyl Rubber

Abstract Different bis-maleimides are found to have different efficiencies and reactivities in the crosslinking of CIIR in the presence of zinc oxide. Although the degrees of crosslinking of CIIR by bis-maleimides cannot be defined absolutely, some trends concerning the efficiencies of the crosslinking are evident. In general, the aromatic bis-maleimides gave higher degrees of crosslinking than the aliphatic analogs. The reactivity and crosslinking efficiency of an individual bis-maleimide is very much affected by its end-to-end chain length and its electronic distribution, resulting from the interaction between the maleimide groups, and from the interaction between the maleimide groups and other functional groups present in the same molecule. The longer the bis-maleimide molecule and the more electron deficient the maleimido double bond, the greater its effectiveness as a crosslinking agent. Other curing mechanisms, possibly including polymerization of the maleimido groups, appear to be operative when using aromatic bis-maleimides as curing agents for CIIR.

scholarly journals A new synthetic route to methyl (-)-shikimate by asymmetric diels-alder reaction of (S)s-3-(2-pyridylsulfinyl)acrylate.

1988 ◽  
Vol 36 (8) ◽  
pp. 3213-3215 ◽  
Author(s):  
Tamiko Takahashi ◽  
Toshie Namiki ◽  
Yoshio Takeuchi ◽  
Toru Koizumi
Keyword(s):  
Alder Reaction ◽  
Diels Alder ◽  
Synthetic Route ◽  
Diels Alder Reaction

Hetero-Diels-Alder Reactions of 2H-Phospholes with Allenes: Synthesis and Functionalization of 6-Methylene-1-phosphanorbornenes

2021 ◽  
Author(s):  
Keke Zhang ◽  
Qiao-Yu Zhang ◽  
Donghui Wei ◽  
Rongqiang Tian ◽  
Zheng Duan
Keyword(s):  
Double Bond ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Reaction Proceeds ◽  
High Yields

The phospha-Diels–Alder reaction between 2H-phospholes and arylallenes afford 6-methylene-1-phosphanorbornenes in high yields and excellent regioselectivity. This Diels–Alder reaction proceeds at the internal C=C double bond of allenes selectively. The DFT...

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