scholarly journals Stereoselective synthesis of (-)-tetrahydropyrenophorol

2020 ◽  
Vol 85 (9) ◽  
pp. 1129-1136
Author(s):  
Vyasabhattar Ramanujan ◽  
Shaik Sadikha ◽  
Kumar Pavan
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Synthetic Approach ◽  
Asymmetric Dihydroxylation ◽  
Linear Manner ◽  
Related Compounds

Tetrahydropyrenophorol, an interesting macrodiolide, was isolated from the plant Fagonia cretica. The total synthesis of (?)-1-tetrahydropyrenophorol was achieved in an elegant and linear manner from readily an accessible racemic epoxide. The archetypal reactions include regioselective opening of the epoxide, Sharpless asymmetric dihydroxylation, and Mitsunobu cyclodimerization to construct the requisite 16-membered bis-lactone. The synthetic approach demonstrated here is very simple and could be used for the syntheses of related compounds in an economic and highly stereoselective way.

scholarly journals A new approach toward the total synthesis of (+)-batzellaside B

2012 ◽  
Vol 8 ◽  
pp. 1831-1838 ◽  
Author(s):  
Jolanta Wierzejska ◽  
Shin-ichi Motogoe ◽  
Yuto Makino ◽  
Tetsuya Sengoku ◽  
Masaki Takahashi ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Pyroglutamic Acid ◽  
Acetoxy Group ◽  
Synthetic Approach ◽  
New Approach ◽  
Asymmetric Dihydroxylation

A new synthetic approach to (+)-batzellaside B from naturally abundant L-pyroglutamic acid is presented in this article. The key synthetic step involves Sharpless asymmetric dihydroxylation of an olefinic substrate functionalized with an acetoxy group to introduce two chiral centres diastereoselectively into the structure. Heterocyclic hemiaminal 4, which could be converted from the resulting product, was found to provide stereospecific access to enantiomerically enriched allylated intermediate, offering better prospects for the total synthesis of this natural product.

Total Synthesis of Camptothecins: An Update

Synlett ◽  
2017 ◽  
Vol 28 (10) ◽  
pp. 1134-1150 ◽  
Author(s):  
Fen-Er Chen ◽  
Lei Chen
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Enantioselective Synthesis ◽  
The Novel ◽  
Asymmetric Dihydroxylation ◽  
New Methods ◽  
Considerable Research ◽  
Catalytic Asymmetric ◽  
Synthetic Approaches ◽  
Asymmetric Hydroxylation

Over the last few decades, considerable research efforts have been directed toward the development of effective chemical syntheses of camptothecin and its analogs. The last comprehensive review of this area was published in 2003 and many effective new methods have since been reported for the stereoselective synthesis of the camptothecin alkaloids. In this account, we have summarized most of the novel synthetic approaches developed for the synthesis of camptothecins during the last decade. We have focused on strategies for the construction of the pentacyclic ring system and the different methods used to install the chiral quaternary center on the E ring of camptothecin.1 Introduction2 Synthesis of Racemic Camptothecins3 Enantioselective Synthesis of Camptothecins3.1 Sharpless Asymmetric Dihydroxylation3.2 Catalytic Asymmetric Cyanosilylation3.3 Auxiliary-Induced Asymmetric Carbonyl Addition3.4 Catalytic Asymmetric Ethylation3.5 Asymmetric Hydroxylation4 Conclusion

scholarly journals Total Synthesis of Hybocarpone, a Cytotoxic Naphthazarin Derivative from the Lichen Lecanora hybocarpa, and Related Compounds

2014 ◽  
Vol 9 (12) ◽  
pp. 1934578X1400901 ◽  
Author(s):  
Sergey V. Dragan ◽  
Michael A. Pushilin ◽  
Valery P. Glazunov ◽  
Vladimir A. Denisenko ◽  
Victor Ph. Anufriev
Keyword(s):  
Total Synthesis ◽  
Antitumor Agent ◽  
Synthetic Approach ◽  
Oxidative Dimerization ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds ◽  
Related Compounds

The concise synthesis of the lichen-derived antitumor agent hybocarpone (1) and its analogs is described. A new synthetic approach is based on the direct oxidative dimerization of the available naphthazarin precursors in the formation of the binaphtho[2,3- b; 2,3- d]furantetraone structure. It was shown that the first step to tetrahydrofuran features is the bridging hindered S*, S* and R*, S* carbon-carbon bonds of the molecules, setting the relative configurations of the 5a S*,6a S*,12a S*,12b S* and 5a S*,6a R*,12a R*,12b S* diastereomers.

General Cyclopropane Assembly via Enantioselective Redox-Active Carbene Transfer to Aliphatic Olefins

2018 ◽  
Author(s):  
Marc Montesinos-Magraner ◽  
Matteo Costantini ◽  
Rodrigo Ramirez-Contreras ◽  
Michael E. Muratore ◽  
Magnus J. Johansson ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Chemical Space ◽  
Synthetic Approach ◽  
Asymmetric Cyclopropanation ◽  
Redox Active ◽  
Wide Range ◽  
Leaving Group ◽  
Stereoelectronic Properties ◽  
Carbene Transfer

Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates and reagents, even when targeting similar compounds. This limits the speed and chemical space available for discovery campaigns. Here we introduce a practical and versatile diazocompound, and we demonstrate its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. We found that the redox-active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect enabled the asymmetric cyclopropanation of a wide range of olefins including unactivated aliphatic alkenes, enabling the 3-step total synthesis of (–)-dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally-differentiated diazocompounds are viable and advantageous equivalents of single-carbon chirons<i>.</i>

Concise Total Synthesis of Curvulone B

Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring System ◽  
Bond Forming ◽  
Cross Metathesis ◽  
Bond Forming Reactions ◽  
Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

Total Synthesis ofdl-Ascofuranone and Related Compounds

1995 ◽  
Vol 68 (9) ◽  
pp. 2727-2734 ◽  
Author(s):  
Hiroyuki Saimoto ◽  
Shin-ichiro Ohrai ◽  
Hitoshi Sashiwa ◽  
Yoshihiro Shigemasa ◽  
Tamejiro Hiyama
Keyword(s):  
Total Synthesis ◽  
Related Compounds
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