scholarly journals Synthesis of the Trans-Syn-Trans Perhydrobenzo[f]chromene Ring System

2021 ◽  
Author(s):  
Amjad Ayad Qatran AlKhdhairawi ◽  
Syahrul Imran ◽  
Nurhuda Manshoor ◽  
Geoffrey A. Cordell ◽  
Narendra Babu Shivanagere Nagojappa ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Ring System ◽  
Unsaturated Ketone ◽  
Target Compound ◽  
Reductive Alkylation ◽  
Acid Catalyzed ◽  
Key Steps ◽  
Chromene Ring

<p>A stereoselective synthesis of the <i>trans</i>-<i>syn</i>-<i>trans </i>perhydrobenzo[<i>f</i>]chromene skeleton is presented. The target compound <b>3 </b>was achieved in six steps starting from the (<i>S</i>)-(+)-Wieland-Miescher ketone. Key steps include the sp<sup>2</sup> alkylation at the a-carbon of an unsaturated ketone, Birch-type reductive alkylation, and an acid-catalyzed cyclization. </p>

scholarly journals Synthesis of the Trans-Syn-Trans Perhydrobenzo[f]chromene Ring System

2021 ◽  
Author(s):  
Amjad Ayad Qatran AlKhdhairawi ◽  
Syahrul Imran ◽  
Nurhuda Manshoor ◽  
Geoffrey A. Cordell ◽  
Narendra Babu Shivanagere Nagojappa ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Ring System ◽  
Unsaturated Ketone ◽  
Target Compound ◽  
Reductive Alkylation ◽  
Acid Catalyzed ◽  
Key Steps ◽  
Chromene Ring

<p>A stereoselective synthesis of the <i>trans</i>-<i>syn</i>-<i>trans </i>perhydrobenzo[<i>f</i>]chromene skeleton is presented. The target compound <b>3 </b>was achieved in six steps starting from the (<i>S</i>)-(+)-Wieland-Miescher ketone. Key steps include the sp<sup>2</sup> alkylation at the a-carbon of an unsaturated ketone, Birch-type reductive alkylation, and an acid-catalyzed cyclization. </p>

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.

scholarly journals Studies on the Enantioselective Synthesis of E-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 428
Author(s):  
Nihan Yayik ◽  
Maria Pérez ◽  
Elies Molins ◽  
Joan Bosch ◽  
Mercedes Amat
Keyword(s):  
Ring System ◽  
Enantioselective Synthesis ◽  
Synthetic Route ◽  
Hydroxymethyl Group ◽  
Hydride Reduction ◽  
Lactam Carbonyl ◽  
Key Steps ◽  
Oxindole Alkaloids

A synthetic route for the enantioselective construction of the tetracyclic spiro[indolizidine-1,3′-oxindole] framework present in a large number of oxindole alkaloids, with a cis H-3/H-15 stereochemistry, a functionalized two-carbon substituent at C-15, and an E-ethylidene substituent at C-20, is reported. The key steps of the synthesis are the generation of the tetracyclic spirooxindole ring system by stereoselective spirocyclization from a tryptophanol-derived oxazolopiperidone lactam, the removal of the hydroxymethyl group, and the stereoselective introduction of the E-ethylidene substituent by acetylation at the α-position of the lactam carbonyl, followed by hydride reduction and elimination. Following this route, the 21-oxo derivative of the enantiomer of the alkaloid 7(S)-geissoschizol oxindole has been prepared.

Stereoselective Synthesis of C-Ketosides by Lewis Acid Catalyzed C-Glycosylation of Alkynyl-Ketoses.

ChemInform ◽  
2003 ◽  
Vol 34 (14) ◽  
Author(s):  
Ana M. Gomez ◽  
Clara Uriel ◽  
Serafin Valverde ◽  
Slawomir Jarosz ◽  
J. Cristobal Lopez
Keyword(s):  
Lewis Acid ◽  
Stereoselective Synthesis ◽  
Acid Catalyzed

scholarly journals (6-Methoxy-2-oxo-2H-chromen-4-yl)methyl morpholine-4-carbodithioate

2013 ◽  
Vol 69 (2) ◽  
pp. o192-o192 ◽  
Author(s):  
H. C. Devarajegowda ◽  
K. Mahesh Kumar ◽  
S. Seenivasa ◽  
H. K. Arunkashi ◽  
O. Kotresh
Keyword(s):  
Hydrogen Bond ◽  
Bond Angle ◽  
Chair Conformation ◽  
Ring System ◽  
Maximum Deviation ◽  
Compound C ◽  
Centroid Distance ◽  
Benzene Rings ◽  
Morpholine Ring ◽  
Chromene Ring

In the title compound, C16H17NO4S2, the 2H-chromene ring system is nearly planar, with a maximum deviation of 0.070 (1) Å, and the morpholine ring adopts a chair conformation; the bond-angle sum for its N atom is 357.9°. The dihedral angle between the the 2H-chromene ring and the best plane through the morpholine ring is 89.09 (6)°. An intramolecular C—H...S hydrogen bond occurs. In the crystal, C—H...O hydrogen bonds generateR22(8) rings and π–π interactions occur between fused benzene rings of the chromene system [shortest centroid–centroid distance = 3.5487 (8) Å].

First Total Synthesis of a Fluorinated Calystegin

2010 ◽  
Vol 65 (4) ◽  
pp. 445-451 ◽  
Author(s):  
René Csuk ◽  
Erik Prell ◽  
Stefan Reißmann ◽  
Claudia Korb
Keyword(s):  
Total Synthesis ◽  
Ring Opening ◽  
Competitive Inhibitor ◽  
Ring Closure ◽  
Target Compound ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Ring Opening Reaction ◽  
Ultrasound Assisted ◽  
Key Steps

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.

ChemInform Abstract: Stereoselective Synthesis of the Pyrroloisoquinoline Ring System.

ChemInform ◽  
2010 ◽  
Vol 32 (35) ◽  
pp. no-no
Author(s):  
Steven M. Allin ◽  
Stella L. James ◽  
William P. Martin ◽  
Timothy A. D. Smith
Keyword(s):  
Stereoselective Synthesis ◽  
Ring System
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