Thiol esters in organic synthesis. XIV. The total synthesis of racemic α-costal

1986 ◽  
Vol 64 (4) ◽  
pp. 658-666 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Hla Wynn
Keyword(s):  
Total Synthesis ◽  
Organic Synthesis ◽  
Salient Feature ◽  
Tert Butyl ◽  
Racemic Form ◽  
Thiol Esters

The first total synthesis of α-costal (1) in racemic form has been achieved in an unequivocal manner whereby the structure previously assigned to the natural aldehyde is confirmed. A salient feature of the synthesis is the use of S-tert-butyl cyanothiolacetate to facilitate the introduction of the labile acrolein unit.

scholarly journals 3-Trifluoromethylcephalosporins. I. Total synthesis of tert-butyl (.+-.)-7-amino-3-trifluoromethyl-3-cephem-4-carboxylate.

1980 ◽  
Vol 28 (1) ◽  
pp. 62-69 ◽  
Author(s):  
TAIICHIRO WATANABE ◽  
YOICHI KAWANO ◽  
TERUO TANAKA ◽  
TOSHIHIKO HASHIMOTO ◽  
TETSUO MIYADERA
Keyword(s):  
Total Synthesis ◽  
Tert Butyl

Synthesis of Optically Active Hydroxyalkyl Cycloheptatrienes: A Key Step in the Total Synthesis of 6,11-Methylene-LXB4

Synlett ◽  
2020 ◽  
Vol 32 (01) ◽  
pp. 45-50
Author(s):  
Udo Nubbemeyer ◽  
Analuisa Nava ◽  
Lukas Trippe ◽  
Andrea Frank ◽  
Lars Andernach ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Total Synthesis ◽  
Structure Elucidation ◽  
Butyl Ester ◽  
Optically Active ◽  
Chiral Hplc ◽  
Reaction Conditions ◽  
Acid Product ◽  
Tert Butyl ◽  
Nabh4 Reduction

AbstractStarting from methyl cycloheptatrienyl-1-carboxylate, 6-acylation was successfully achieved employing glutaryl chloride in the presence of AlCl3 under controlled reaction conditions to furnish keto carboxylic acid product. After protection of this keto carboxylic acid as tert-butyl ester, reagent-controlled enantioselective reductions delivered configuration-defined methyl-6-hydroxylalkyl cycloheptatriene-1-carboxylates with up to 80% ee. Whereas simple NaBH4 reduction of the keto carboxylic acid and subsequent lactonization afforded a methyl-6-tetrahydropyranonyl cycloheptatriene-1-carboxylate. Resolution using chiral HPLC delivered the product enantiomers with up to >99% ee Finally, ECD analyses enabled structure elucidation. The products are used as key intermediates in enantioselective 6,11-methylene-lipoxin B4 syntheses.

scholarly journals Asymmetric Synthesis of Quinine: A Landmark in Organic Synthesis

2006 ◽  
Vol 1 (10) ◽  
pp. 1934578X0600101 ◽  
Author(s):  
Vijay Nair ◽  
Rajeev S. Menon ◽  
Sreekumar Vellalath
Keyword(s):  
Organic Chemistry ◽  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Organic Synthesis ◽  
Chemical Industry ◽  
Crucial Role ◽  
Historical Perspective ◽  
Modern Medicine ◽  
Present Review ◽  
Catalytic Asymmetric Synthesis

Ever since its isolation in 1820, Quinine has played a crucial role in the development of organic chemistry, the chemical industry and modern medicine. A total synthesis of quinine, widely regarded as an event of epochal importance, was claimed by Woodward and Doering in 1945. This work, however, heavily relied on unsubstantiated literature reports and it appears that Woodward's work fell short of a total synthesis of quinine. The first total synthesis of quinine was reported by Uskokovic in the 1970s. The first stereoselective total synthesis of quinine was accomplished only in 2001, by Stork, who incidentally is the originator of the concept of stereoselectivity in total synthesis. Apart from the stereoselectivity, Stork's synthesis of quinine is remarkable for its conceptual uniqueness and retrosynthetic novelty. Naturally, this work has been attested as a landmark in organic synthesis by leaders in the field. Subsequently, Jacobson and Kobayashi reported the catalytic asymmetric synthesis of quinine in 2003 and 2004, respectively. Both these synthesis have followed a similar approach. The present review has attempted to provide a concise account of the synthesis of quinine from a historical perspective.

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