Total Synthesis of (−)-Kainic Acid via Intramolecular Michael Addition: A Second-Generation Route

2008 ◽  
Vol 10 (9) ◽  
pp. 1711-1714 ◽  
Author(s):  
Hiroshi Sakaguchi ◽  
Hidetoshi Tokuyama ◽  
Tohru Fukuyama
Keyword(s):  
Total Synthesis ◽  
Kainic Acid ◽  
Michael Addition ◽  
Second Generation

scholarly journals Towards the total synthesis of keramaphidin B

2016 ◽  
Vol 12 ◽  
pp. 1096-1100 ◽  
Author(s):  
Pavol Jakubec ◽  
Alistair J M Farley ◽  
Darren J Dixon
Keyword(s):  
Total Synthesis ◽  
Michael Addition ◽  
Synthetic Strategy

The enantio- and diastereoselective Michael addition of a δ-valerolactone-derived pronucleophile to a substituted furanyl nitroolefin catalysed by a bifunctional cinchonine-derived thiourea has been used as the key stereocontrolling step in a new synthetic strategy to the heavily functionalised piperidine core of keramaphidin B.

Second-generation total synthesis of (−)-diversifolin

2010 ◽  
Vol 51 (14) ◽  
pp. 1876-1879 ◽  
Author(s):  
Kazuma Tsuboi ◽  
Tomoaki Nakamura ◽  
Takahiro Suzuki ◽  
Atsuo Nakazaki ◽  
Susumu Kobayashi
Keyword(s):  
Total Synthesis ◽  
Second Generation

Synthesis of 14-hydroxy steroids. Total synthesis of methyl 14β-hydroxy-1,7,17-trioxo-5β,8-androstene-10β-oate and related compounds

1990 ◽  
Vol 68 (11) ◽  
pp. 1917-1922 ◽  
Author(s):  
Réjean Ruel ◽  
Pierre Deslongchamps
Keyword(s):  
Total Synthesis ◽  
Ammonium Salt ◽  
Michael Addition ◽  
Title Compound ◽  
Steroid Synthesis ◽  
Related Compounds ◽  
Acetylenic Ketone

The total synthesis of the title compound 22 and methyl 14α-hydroxy-5β,13α,8-androstene-1,7,17-trioxo-10β-oate 21 isomer is reported. We also describe the 1,6-Michael addition of 2-methyl-1,3-cyclopentanedione on dienone 14 and the protic ammonium salt catalyzed intramolecular Michael addition of cyclic β-ketoester on the conjugated acetylenic ketone 13. Keywords: cardenolides, steroid synthesis, aldol, Michael addition.

An enantiospecific total synthesis of (–)-α-kainic acid

1987 ◽  
pp. 1220-1222 ◽  
Author(s):  
Jeremy Cooper ◽  
David W. Knight ◽  
Peter T. Gallagher
Keyword(s):  
Total Synthesis ◽  
Kainic Acid

Alkene Metathesis: Synthesis of Kainic Acid, Pladienolide B and Amphidinolide Y

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Kainic Acid ◽  
Second Generation ◽  
Tumor Regression ◽  
Human Cancer ◽  
Cross Coupling ◽  
Side Reaction ◽  
Chiral Auxiliary ◽  
Crotonyl Chloride ◽  
The University

As alkene metathesis has developed into one of the tools of organic synthesis, many practical questions have arisen. In the course of a synthesis (Organic Lett. 2007, 9, 1635) of the important neuropharmacological tool (-)-kainic acid 7, Tohru Fukuyama of the University of Tokyo prepared the key intermediate 1 by chiral auxiliary mediated coupling of crotonyl chloride with acetadehyde. Dibal reduction gave the hemiaminal, which underwent reductive amination with glycine methyl ester, leading to the alkene 2. Alkene metathesis of the derived ester 3 to form the unsaturated lactone 4 was then examined in detail. It was found that 0.5 mol % of the second generation Hoveyda catalyst was sufficient to cyclize 3 to 4 in 92% yield. With 0.8 mol %, the yield was 99%. The key to the efficacy of this cyclization was the use of 1,2-dichloroethane at reflux as the reaction solvent. The macrolide pladienolide D 14 induces in vivo tumor regression in several human cancer xenograft models. This activity was important enough that a team at Esai Co., Ltd in Tsukuba headed by Yoshihiko Kotake undertook the total synthesis (Angew. Chem. Int. Ed. 2007, 46, 4350). Their approach used two alkene metathesis steps. To prepare the substrate for the macrolide construction, the alcohol 8 and the acid 9, each prepared by chiral auxiliary control, were coupled to give the ester 10. An extensive investigation led to alkene metathesis conditions that were satisfactory, the use of the second generation Hoveyda catalyst in refluxing toluene. A significant competing side reaction was the migration of the monosubstituted alkene of 10 to make the alkenyl ether. The second alkene metathesis step was the coupling of 12 with 13. The most effective catalyst in this case was the second generation Grubbs. Note that the free alcohol 13 participated successfully in the cross-coupling. According to the authors, this is one of just a few examples of successful cross coupling of an alkene adjacent to a quaternary center. The stereocontrolled construction of trisubstituted alkenes by metathesis is a particular challenge.

Intramolecular Michael Addition of N- and O-Centred Nucleophiles to Tethered Acrylates. The Role of Double-Bond Geometry in Controlling the Diastereo- selectivity of Cyclizations Leading to 2,6-Disubstituted Tetrahydropyrans and Piperidines.

1998 ◽  
Vol 51 (1) ◽  
pp. 9 ◽  
Author(s):  
Martin G. Banwell ◽  
Brett D. Bissett ◽  
Chinh T. Bui ◽  
Ha T. T. Pham ◽  
Gregory W. Simpson
Keyword(s):  
Double Bond ◽  
Total Synthesis ◽  
Michael Addition ◽  
Reductive Amination ◽  
Major Product ◽  
Enantioselective Synthesis ◽  
Cyclization Reactions ◽  
Glandular Secretion

The oxyanion derived from hydroxyacrylate E-(5) undergoes smooth intramolecular Michael addition to give the trans-2,6-disubstituted tetrahydropyran (7) as the major product of reaction. In contrast, the oxyanion obtained from isomer Z-(5) cyclizes to give the cis-2,6-disubstituted tetrahydropyran (6) as the major product. Such chemistry has been extended to the enantioselective synthesis of (+)-(6) the acquisition of which constitutes a formal total synthesis of acid (+)-(2), a constituent of the glandular secretion from the civet cat (Viverra civetta). Reductive amination of keto acrylate (12) affords an intermediate amine which cyclizes, in situ, to give the cis-2,6-disubstituted piperidine (26). Analogous treatment of compound (13) delivers the isomeric trans-2,6-disubstituted piperidine (27) as the exclusive product of reaction. Transition state structures have been proposed to account for the diastereoselectivities observed in all of the cyclization reactions.

scholarly journals Second Generation Synthesis of the Neo-Clerodane Diterpenoid Methyl Barbascoate

2013 ◽  
Vol 8 (7) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Hisahiro Hagiwara ◽  
Naomi Honma ◽  
Kimihiko Kinugawa ◽  
Shota Sato ◽  
Takashi Hoshi ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Second Generation ◽  
Samarium Diiodide ◽  
Conjugate Reduction ◽  
Palladium Catalyzed ◽  
Clerodane Diterpenoid

The second generation total synthesis of the neo-clerodane diterpenoid, methyl barbascoate, was accomplished in seven or nine linear steps via double enol triflation and subsequent palladium catalyzed double carbonylation, followed by regioselective samarium diiodide mediated conjugate reduction.

The Total Synthesis of Spermine Alkaloid Kukoamine Bimesylate

Synlett ◽  
2018 ◽  
Vol 29 (20) ◽  
pp. 2669-2672
Author(s):  
Kai Dong
Keyword(s):  
Total Synthesis ◽  
Michael Addition ◽  
Addition Reaction ◽  
Cyano Group ◽  
Michael Addition Reaction ◽  
Amino Groups ◽  
Competitive Reaction ◽  
12 Steps ◽  
Cyano Groups

The first total synthesis of kukoamine B bimesylate was completed from 1,4-diaminobutane dihydrochloride in 12 steps with a 11.4% overall yield, and all the steps could be carried out at a kilogram scale. The cyano groups were used as the precursor of amino groups to avoid the competitive reaction delicately. The aza-Michael addition reaction, amidation and hydrogenation of the cyano group sequence was streamlined as a general approach towards the synthesis of polyamine structures.

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