scholarly journals A Unified Total Synthesis of Isocyclocapitelline and Cyclocapitelline

2020 ◽  
Vol 15 (11) ◽  
pp. 1934578X2096787
Author(s):  
Marepally Srilatha ◽  
Vallabhareddy Satteyyanaidu ◽  
Chepyala Krishna Reddy ◽  
Venkata Subba Reddy Basireddy

A facile and concise synthesis of β-carboline alkaloids, such as (–)-isocyclocapitelline and (+)-cyclocapitelline, has been achieved from commercially available geraniol through a unified strategy. The key steps involved in this synthesis are Sharpless epoxidation, intramolecular ring opening of epoxide, Pictet-Spengler reaction, and dehydrogenative aromatization using 10% palladium/carbon in xylene under neutral conditions.

2018 ◽  
Vol 13 (8) ◽  
pp. 1934578X1801300 ◽  
Author(s):  
Chaya N Dhudmal ◽  
Dhanraj O Biradar ◽  
Maddipatla V. Satyanarayana ◽  
Basi V Subba Reddy

Stereoselective total synthesis of 1,4-dideoxy-1,4-imino-L-ribitol has been accomplished from D-glucose. The key step involved in this synthesis is the regioselective ring-opening of the epoxide with a tethered amido group to give the N-tosyl-3,6-dideoxy-3,6-imino-1,2- O-isopropylidene-α-D-glucofuranose.


2010 ◽  
Vol 65 (4) ◽  
pp. 445-451 ◽  
Author(s):  
René Csuk ◽  
Erik Prell ◽  
Stefan Reißmann ◽  
Claudia Korb

A straightforward chiral pool synthesis for the first fluorinated calystegin is described. Key steps of this synthesis include an ultrasound-assisted Zn-mediated tandem ring opening reaction followed by a Grubbs’ catalyst-mediated ring closure metathesis reaction. The target compound is a selective and competitive inhibitor for a β -glycosidase.


Synthesis ◽  
2017 ◽  
Vol 49 (11) ◽  
pp. 2483-2487 ◽  
Author(s):  
Ambati Sharada ◽  
Kundeti Rao ◽  
Jhillu Yadav ◽  
Tadikamalla Rao ◽  
Kommu Nagaiah

A stereoselective synthesis of (6R,7R,8S)-8-chlorogoniodiol has been achieved in a linear sequence of 12 steps and 19.8% overall yield from cinnamyl alcohol. The key steps include Sharpless asymmetric epoxidation, regioselective ring opening of epoxide, indium-mediated Barbier allylation, and Still–Gennari olefination.


2015 ◽  
Vol 51 (89) ◽  
pp. 16143-16146 ◽  
Author(s):  
Wen-Fang Qin ◽  
T. Xiao ◽  
D. Zhang ◽  
Lin-Feng Deng ◽  
Y. Wang ◽  
...  

Asymmetric total synthesis of (−)-depyranoversicolamide B (12) is described from easily prepared chiral pyrroloindoline 21. Key steps in the synthesis are reductive ring opening of the pyrrolo ring in 21 and stereoselective intramolecular Diels–Alder reaction of 18.


Synthesis ◽  
2017 ◽  
Vol 50 (03) ◽  
pp. 663-675
Author(s):  
Pabbaraja Srihari ◽  
Ramakrishna Sayini

The C1–C9 and C10–C24 segments of the 24-membered polyene macrolide macrolactin S were synthesized by routes involving an epoxide-ring-opening reaction, an Ohira–Bestmann alkyne formation, a chelation-controlled nucleophilic addition reaction, and a Still–Gennari olefination as key steps. A chiron approach , starting from readily available glucose diacetonide, was used to synthesize a key intermediate, and a convergent approach was adopted for the synthesis of the key C10–C24 fragment.


RSC Advances ◽  
2014 ◽  
Vol 4 (28) ◽  
pp. 14468-14470 ◽  
Author(s):  
Subhash P. Chavan ◽  
Kailash P. Pawar ◽  
Sumanta Garai

A protecting group free asymmetric total synthesis of (−)-venlafaxine is reported. The strategy employs Sharpless epoxidation and regio-selective epoxide ring opening by an in situ generated Gilman reagent as key steps. This paper reports a 53% overall yield in 6 steps for total synthesis of (−)-venlafaxine.


2011 ◽  
Vol 66 (3) ◽  
pp. 317-323
Author(s):  
René Csuk ◽  
Stefan Reißmann ◽  
Ralph Kluge ◽  
Dieter Ströhl ◽  
Claudia Korb

A straightforward chiral pool synthesis for a non-natural calystegin, 3-epi-B2, is described. Key steps of this synthesis include an ultrasound-assisted Zn-mediated tandem ring opening reaction followed by a Grubbs’ catalyst-mediated ring closure metathesis reaction. Compared to calystegin B2, the target compound is no longer an inhibitor for a β -glycosidase hence proving that an equatorial hydroxyl group at position C-3 is necessary for a tight binding of calystegins into the active site of β -glycosidases.


Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar

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.


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