Chemistry of the Coccoidea. VIII. Synthesis of the ancient dyestuff kermesic acid and of related anthraquinones

1981 ◽  
Vol 34 (11) ◽  
pp. 2401 ◽  
Author(s):  
DW Cameron ◽  
DJ Deutscher ◽  
GI Feutrill ◽  
PG Griffiths
Keyword(s):  
Hydroxy Group ◽  
Diels Alder

The insect anthraquinones kermesic acid (3) and laccaic acid D (2) have been synthesized efficiently, as have the plant anthraquinones aloesaponarin-I (4) and -11 (33). The syntheses were based on regiospecific Diels-Alder addition of the silyloxy dienes (10) and (11) to simpler quinones. Regiospecificity was controlled by 2(3)-chloro groups in the dienophiles or, for addition to certain naphthoquinones, by a hydroxy group peri to carbonyl.

Four-step one-pot catalytic asymmetric synthesis of multisubstituted tricyclic compounds: Lipase-catalyzed dynamic kinetic resolution followed by an intramolecular Diels–Alder reaction

Synlett ◽  
2021 ◽  
Author(s):  
Izuru Tsuchimochi ◽  
Shuhei Hori ◽  
Yasuo Takeuchi ◽  
Masahiro Egi ◽  
Tomo-o Satoh ◽  
...  
Keyword(s):  
Hydroxy Group ◽  
Kinetic Resolution ◽  
Alder Reaction ◽  
Diels Alder ◽  
One Pot ◽  
Diels Alder Reaction ◽  
Tricyclic Compounds ◽  
High Yields ◽  
Group Migration ◽  
Oxovanadium Compounds

Starting from readily available tertiary alcohols, four different reactions (i.e., a 1,3-migration of a hydroxy group, kinetic resolution, racemization, and an intramolecular Diels–Alder reaction) took place under the co-catalysis of lipase and oxovanadium compounds in a one-pot process to produce multisubstituted tricyclic carbon frameworks in high yields and high enantioselectivities. The key to the success of this process was the discovery that the silyl group attached to the terminal carbon of the vinyl moiety completely controls the direction of hydroxy group migration.

Synthesis of Coumarins via [4+2] Cyclization of Siloxy Alkynes and Salicylaldehydes

Synlett ◽  
2020 ◽  
Author(s):  
Jianwei Sun ◽  
Hui Qian
Keyword(s):  
Hydroxy Group ◽  
Triple Bond ◽  
Diels Alder ◽  
New Approach ◽  
Polarity Switching ◽  
Wide Range ◽  
Siloxy Alkynes ◽  
Mechanistic Understanding ◽  
Stepwise Formation

AbstractA new approach for the synthesis of coumarins from siloxy alkynes and salicylaldehydes is disclosed. Unlike the previous benzannulation reactions of siloxy alkynes that all proceed by electron-inversed Diels–Alder mechanism, this process represents a new [4+2] cyclization. In the presence of the superior HNTf2 catalyst, a wide range of coumarins were efficiently synthesized. This process was also extended to the synthesis of 2-quinolones. The polarized electron-rich triple bond might react sequentially with the aldehyde and hydroxy group by polarity switching in the stepwise formation of the C–C and C–O bonds. Control experiments provided insights into the mechanistic understanding.

A New Process for the Total Synthesis of Sparstolonin B

Synlett ◽  
2017 ◽  
Vol 28 (10) ◽  
pp. 1187-1190 ◽  
Author(s):  
Haitao Yu ◽  
Xiaohang Tang ◽  
Le Tong ◽  
Mengyi Yao ◽  
Qiaoli Liang ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Hydroxy Group ◽  
Cyano Group ◽  
Diphenyl Ether ◽  
Selective Reduction ◽  
Diels Alder ◽  
Simple Route ◽  
New Process ◽  
Sparstolonin B ◽  
High Yields

A novel and simple route was developed that gives sparstolonin B in high yields from affordable commercial compounds. A Diels–Alder strategy was used for the facile construction of the multisubstituted diphenyl ether. The xanthenone segment was obtained by cyclization in an intramolecular Friedel–Crafts reaction, followed by selective reduction of a ketone group and a transformation from a hydroxy group into a cyano group. The final part of the lactone was directly derived by the reduction of the cyano group with Raney nickel.

Syntheses of Angucyclinones Related to Ochromycinone. III. An 11-Hydroxy Isomer and Some Reduced Analogues

1999 ◽  
Vol 52 (2) ◽  
pp. 129 ◽  
Author(s):  
Tomas Rozek ◽  
Tomas Rozek ◽  
Dennis K. Taylor ◽  
Dennis K. Taylor ◽  
Edward R. T. Tiekink ◽  
...  
Keyword(s):  
Hydroxy Group ◽  
Alder Reaction ◽  
Diels Alder ◽  
X Ray ◽  
X Ray Crystallography ◽  
Diels Alder Reaction ◽  
Stereo Selectivity ◽  
Hydrolysis Of ◽  
Alder Adduct

The boron triacetate assisted Diels Alder reaction between racemic 5,5-dimethyl-3-vinylcyclohex- 2-enyl acetate and 5-hydroxynaphthoquinone yields the racemic 11-hydroxy-3,3-dimethyl-7,12-dioxo- 1,2,3,4,6,6a,7,12,12a,12b-decahydrobenzo[a]anthracen-1-yl acetate as the sole stereoisomer by regio- and stereo-selective cis endo addition. Aromatization of the Diels Alder adduct followed by hydrolysis of the acetate and oxidation of the resultant 1-hydroxy group gives the target angucyclinone, 11-hydroxy-3,3-dimethyl-1,2,3,4,7,12-hexahydrobenzo[a]anthracene-1,7,12-trione, in an overall yield of 37% from 5-hydroxynaphthoquinone. The regio- and stereo-selectivity of the Diels Alder addition is confirmed by a combination of 13C n.m.r. spectroscopy and X-ray crystallography.

2 H-Pyrrolenin-N-oxid und N-Hydroxy-pyrrol.

1976 ◽  
Vol 31 (5) ◽  
pp. 599-604 ◽  
Author(s):  
Richard Kreher ◽  
Hubert Pawelczyk
Keyword(s):  
Hydroxy Group ◽  
Diels Alder ◽  
Mercuric Oxide ◽  
Alder Adduct

Dehydrogenation of N-hydroxy-Δ3-pyrroline with mercuric oxide leads via the cyclic conjugated 2 H-pyrrolenine-N-oxide to the tautomeric N-hydroxy-pyrrole, which has pronounced reactivity towards dienophiles. With N-phenyl-maleic-imide the endoconfigurated Diels-Alder-adduct is formed, whose stability is increased by acylation of the N-hydroxy group. The O-acylated Diels-Alder adducts can be prepared independantly from N-acyloxy-pyrroles and the corresponding dienophile.

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