scholarly journals Enantioselective Synthesis of the Ethyl Analog of the Marine Alkaloid Haliclorensin C

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1069
Author(s):  
Guillaume Guignard ◽  
Núria Llor ◽  
David Pubill ◽  
Joan Bosch ◽  
Mercedes Amat
Keyword(s):  
Building Block ◽  
Amino Alcohol ◽  
Ring Opening ◽  
Enantioselective Synthesis ◽  
Ring Closing Metathesis ◽  
Biological Screening ◽  
Marine Alkaloid ◽  
Key Steps

The enantioselective synthesis (3.7% overall yield in nine steps from 2) and biological screening of the ethyl analog of the macrocyclic marine alkaloid haliclorensin C (compound 5) are reported. Amino alcohol 3, generated by a LiNH2BH3-promoted reductive ring-opening/debenzylation sequence from phenylglycinol-derived lactam 2, was used as the starting chiral linear building block. Incorporation of the undecene chain via the nosyl derivative 12, methylenation of the pentanol moiety, and a ring-closing metathesis are the key steps of the synthesis.

scholarly journals Bidirectional cross metathesis and ring-closing metathesis/ring opening of a C 2-symmetric building block: a strategy for the synthesis of decanolide natural products

2013 ◽  
Vol 9 ◽  
pp. 2544-2555 ◽  
Author(s):  
Bernd Schmidt ◽  
Oliver Kunz
Keyword(s):  
Building Block ◽  
Ring Opening ◽  
Kinetic Resolution ◽  
Membered Ring ◽  
Ring Closure ◽  
Ring Closing Metathesis ◽  
Cross Metathesis ◽  
Key Steps ◽  
A Site ◽  
Site Selective

Starting from the conveniently available ex-chiral pool building block (R,R)-hexa-1,5-diene-3,4-diol, the ten-membered ring lactones stagonolide E and curvulide A were synthesized using a bidirectional olefin-metathesis functionalization of the terminal double bonds. Key steps are (i) a site-selective cross metathesis, (ii) a highly diastereoselective extended tethered RCM to furnish a (Z,E)-configured dienyl carboxylic acid and (iii) a Ru–lipase-catalyzed dynamic kinetic resolution to establish the desired configuration at C9. Ring closure was accomplished by macrolactonization. Curvulide A was synthesized from stagonolide E through Sharpless epoxidation.

A Stereoselective Synthesis of the ACE Inhibitor Trandolapril

Synlett ◽  
2019 ◽  
Vol 30 (07) ◽  
pp. 813-816 ◽  
Author(s):  
Slim Chiha ◽  
Matthias Spilles ◽  
Jörg-Martin Neudörfl ◽  
Hans-Günther Schmalz
Keyword(s):  
Acid Derivative ◽  
Building Block ◽  
Ace Inhibitor ◽  
Stereoselective Synthesis ◽  
Pyroglutamic Acid ◽  
Ring Closing Metathesis ◽  
12 Steps ◽  
Key Steps

A conceptually novel and stereoselective synthesis of the enantiopure octahydroindole building block and its conversion into the ACE inhibitor trandolapril was achieved. Key steps include the α-allylation of a protected l-pyroglutamic acid derivative, a highly diastereoselective Hosomi–Sakurai reaction and a Ru-catalyzed ring-closing metathesis of a 4,5-diallylated proline. This way, the synthesis of trandolapril was efficiently achieved in 25% overall yield (12 steps).

One-Pot Tandem Ring-Opening and Ring-Closing Metathesis Polymerization of Disubstituted Cyclopentenes Featuring a Terminal Alkyne Functionality

2020 ◽  
Vol 53 (11) ◽  
pp. 4330-4337
Author(s):  
Santhosh Kumar Podiyanachari ◽  
Salvador Moncho ◽  
Edward N. Brothers ◽  
Saeed Al-Meer ◽  
Mohammed Al-Hashimi ◽  
...  
Keyword(s):  
Ring Opening ◽  
Terminal Alkyne ◽  
Ring Closing Metathesis ◽  
One Pot ◽  
Metathesis Polymerization

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.

ChemInform Abstract: Enantioselective Synthesis of Bicyclic Compounds via Catalytic 1,4-Addition-Ring Closing Metathesis.

ChemInform ◽  
2010 ◽  
Vol 32 (33) ◽  
pp. no-no
Author(s):  
Robert Naasz ◽  
Leggy A. Arnold ◽  
Adriaan J. Minnaard ◽  
Ben L. Feringa
Keyword(s):  
Enantioselective Synthesis ◽  
Ring Closing Metathesis ◽  
Bicyclic Compounds
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