Asymmetric Diels-Alder Reactions of Chiral (E)-2-Cyanocinnamates. 2. Synthesis of the Four 1-Amino-2-phenyl-1-cyclohexanecarboxylic Acids in Enantiomerically Pure Form

1994 ◽  
Vol 59 (25) ◽  
pp. 7774-7778 ◽  
Author(s):  
Carlos Cativiela ◽  
Alberto Avenoza ◽  
Miguel Paris ◽  
Jesus M. Peregrina
Keyword(s):  
Diels Alder ◽  
Pure Form ◽  
Enantiomerically Pure

Pigments of Fungi. LIX. Synthesis of (1S,3S)- and (1R,3R)-Austrocortilutein and (1S,3S)-Austrocortirubin from Citramalic Acid

2000 ◽  
Vol 53 (4) ◽  
pp. 245 ◽  
Author(s):  
Melvyn Gill ◽  
Michael F. Harte ◽  
Abilio Ten
Keyword(s):  
Natural Products ◽  
Diels Alder ◽  
Pure Form ◽  
Enantiomerically Pure ◽  
Naturally Occurring ◽  
First Time

The naturally occurring tetrahydroanthraquinone (1S,3S)-austrocortilutein (1) is synthesized for the first time in enantiomerically pure form by Diels–Alder cycloaddition between the functionalized butadiene derivative (8) and the chiral 1,3-dihydroxy-1,2,3,4-tetrahydro-5,8-naphthoquinone (9), the latter being derived from (R)-citramalic acid (3). The natural products (1S,3S)-austrocortirubin (2) and (1R,3R)-austrocortilutein (5) were also prepared for the first time by using the same strategy.

Pigments of Fungi. LXIII. Synthesis of (1S,3R)- and (1R,3S)-Austrocortilutein and the Enantiomeric Purity of Austrocortilutein in some Australian Dermocybe Toadstools

2000 ◽  
Vol 53 (1) ◽  
pp. 41 ◽  
Author(s):  
Catherine Elsworth ◽  
Melvyn Gill ◽  
Evelin Raudies ◽  
Abilio Ten
Keyword(s):  
Stationary Phase ◽  
Chiral Stationary Phase ◽  
Enantiomeric Purity ◽  
Diels Alder ◽  
Pure Form ◽  
Enantiomerically Pure ◽  
Naturally Occurring ◽  
First Time

The naturally occurring tetrahydroanthraquinones (1S,3R)- and (1R,3S)-austrocortilutein (1b) and (1d), respectively, are synthesized for the first time in enantiomerically pure form by Diels–Alder cycloaddition between the functionalized butadiene derivative (4) and the corresponding monochiral trans-1,3-dihydroxy-1,2,3,4- tetrahydro-5,8-naphthoquinone (5a) or (5b), themselves derived from citramalic acid. Separation of the four stereoisomeric austrocortiluteins by using h.p.l.c. over a chiral stationary phase reveals that the enantiomeric purity of the (1S,3S)- and (1R,3R)-quinones (1a) and (1c) varies from species to species whereas the (1S,3R)-isomer (1b) is, in the five cases examined, enantiomerically pure.

Simple and efficient synthesis of allo- and threo-3,3′-dimethylcystine derivatives in enantiomerically pure form

2008 ◽  
Vol 19 (12) ◽  
pp. 1425-1429 ◽  
Author(s):  
R.B. Nasir Baig ◽  
V. Sai Sudhir ◽  
Srinivasan Chandrasekaran
Keyword(s):  
Pure Form ◽  
Efficient Synthesis ◽  
Enantiomerically Pure

Synthesis of Naturally Occurring Cyclic Ethers: Boivivianin B (Murakami), SC- Δ 13 -9-IsoF (Taber), Brevisamide (Panek, Lindsley,Ghosh), Gambierol (Mori)

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Absolute Configuration ◽  
Cyclic Ether ◽  
Diels Alder ◽  
Synthetic Methods ◽  
Hydroxy Ketone ◽  
Total Syntheses ◽  
Enantiomerically Pure ◽  
Boston University ◽  
Gambierdiscus Toxicus ◽  
The University

The challenge of controlling the relative and absolute configuration of highly substituted cyclic ether-containing natural products continues to stimulate the development of new synthetic methods. Masahiro Murakami of Kyoto University showed (J. Org. Chem. 2009, 74, 6050) that Rh-mediated addition of an aryl boronic acid to 1 proceeded with high syn diastereocontrol, giving 3. This set the stage for Au-mediated rearrangement, leading to 4. We found (J. Org. Chem. 2009, 74, 5516) that asymmetric epoxidation of 5 followed by exposure to AD-mix could be used to prepare each of the four diastereomers of 6. We carried 6 on the isofuran 7, using a stereodivergent strategy that allowed the preparation of each of the 32 enantiomerically pure diastereomers of the natural product. Following up on the synthesis of brevisamide 16 described (Organic Highlights, November 16, 2009) by Kazuo Tachibana of the University of Tokyo, three groups reported alternative total syntheses. James S. Panek of Boston University prepared (Organic Lett. 2009, 11, 4390) the cyclic ether of 16 by addition of the enantiomerically pure silane 9 to 8. Craig W. Lindsley of Vanderbilt University used (Organic Lett. 2009, 11, 3950) SmI2 to effect the cyclization of 11 to 12. Arun K. Ghosh of Purdue University employed (Organic Lett. 2009, 11, 4164) an enantiomerically pure Cr catalyst to direct the absolute configuration in the hetero Diels-Alder addition of 14 to 13. Rubottom oxidation of the enol ether so formed led to the α-hydroxy ketone 15. Yuji Mori of Meijo University described (Organic Lett. 2009, 11, 4382) the total synthesis of the Gambierdiscus toxicus ladder ether gambierol 19. A key strategy, used repeatedly through the sequence, was the exo cyclization of an epoxy sulfone, illustrated by the conversion of 17 to 18. The epoxy sulfones were prepared by alkylating the anions derived from preformed epoxy sulfones such as 20.

Diels-Alder Cycloaddition: (+)-Armillarivin (Banwell), Gelsemiol (Gademann), (+)-Frullanolide (Liao), Myceliothermophin A (Uchiro), Peribysin E (Reddy), Caribenol A (Li/Yang)

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Elevated Pressure ◽  
Diels Alder ◽  
Cope Rearrangement ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Enantiomerically Pure ◽  
Peking University ◽  
National University ◽  
Diastereoselective Addition ◽  
The University

Martin G. Banwell of the Australian National University prepared (Org. Lett. 2013, 15, 1934) the enantiomerically pure diol 1 by fermentation of the aromatic precursor. Diels-Alder addition of cyclopentenone 2 proceeded well at elevated pressure to give 3, the precursor to (+)-armillarivin 4. Karl Gademann of the University of Basel found (Chem. Eur. J. 2013, 19, 2589) that the Diels-Alder addition of 6 to 5 proceeded best without solvent and with Cu catalysis to give 7. Reduction under free radical conditions led to gelsemiol 8. Chun-Chen Liao of the National TsingHua University carried out (Org. Lett. 2013, 15, 1584) the diastereoselective addition of 10 to 9. A later oxy-Cope rearrangement established the octalin skeleton of (+)-frullanolide 12. D. Srinivasa Reddy of CSIR-National Chemical Laboratory devised (Org. Lett. 2013, 15, 1894) a strategy for the construction of the angularly substituted cis-fused aldehyde 15 based on Diels-Alder cycloaddition of 14 to the diene 13. Further transformation led to racemic peribysin-E 16. An effective enantioselective catalyst for dienophiles such as 14 has not yet been developed. Hiromi Uchiro of the Tokyo University of Science prepared (Tetrahedron Lett. 2012, 53, 5167) the bicyclic core of myceliothermophin A 19 by BF3•Et2O-promoted cyclization of the tetraene 17. The single ternary center of 17 mediated the formation of the three new stereogenic centers of 18, including the angular substitution. En route to caribenol A 22, Chuang-Chuang Li and Zhen Yang of the Peking University Shenzen Graduate School assembled (J. Org. Chem. 2013, 78, 5492) the triene 20 from two enantiomerically pure precursors. Inclusion of the radical inhibitor BHT sufficed to suppress competing polymerization, allowing clean cyclization to 21. Methylene blue has also been used (J. Am. Chem. Soc. 1980, 102, 5088) for this purpose.

Chemoenzymatic synthesis of antiinflammatory drugs in enantiomerically pure form

2000 ◽  
Vol 11 (11) ◽  
pp. 2403-2407 ◽  
Author(s):  
Amit Basak ◽  
Ahindra Nag ◽  
Gautam Bhattacharya ◽  
Subrata Mandal ◽  
Sikha Nag
Keyword(s):  
Pure Form ◽  
Chemoenzymatic Synthesis ◽  
Antiinflammatory Drugs ◽  
Enantiomerically Pure
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