New Versatile Fluorinated Chiral Building Blocks:  Synthesis and Reactivity of Optically Pure α-(Fluoroalkyl)-β-sulfinylenamines

1996 ◽  
Vol 61 (10) ◽  
pp. 3375-3387 ◽  
Author(s):  
Alberto Arnone ◽  
Pierfrancesco Bravo ◽  
Silvia Capelli ◽  
Giovanni Fronza ◽  
Stefano V. Meille ◽  
...  
Keyword(s):  
Building Blocks ◽  
Optically Pure

Synthesis of Optically Pure 2-Aziridinemethanols: Versatile Synthetic Building Blocks.

1994 ◽  
Vol 42 (11) ◽  
pp. 2241-2250 ◽  
Author(s):  
Nobutaka FUJII ◽  
Kazuo NAKAI ◽  
Hiromu HABASHITA ◽  
Yuka HOTTA ◽  
Hirokazu TAMAMURA ◽  
...  
Keyword(s):  
Building Blocks ◽  
Optically Pure

Optically Pure Aminopolyols and Polyoxamic Acid Derivatives from Aziridine-2-carboxylates

1999 ◽  
Vol 52 (4) ◽  
pp. 259 ◽  
Author(s):  
Heribert Dollt ◽  
Volker Zabel
Keyword(s):  
Solvent Effects ◽  
Michael Addition ◽  
Building Blocks ◽  
Bulky Substituent ◽  
Cis And Trans ◽  
Optically Pure ◽  
The Michael Addition

Various new chiral building blocks could easily be prepared from optically pure cis and trans ethyl 3-(1′,3′- dioxolan-4′-yl)aziridine-2-carboxylates. A stereochemically pure 1,3-dioxolan in the allyl position of an α-bromoacrylate induced a high (3R*,4′S*) selectivity in the Michael addition with an amine. After oxygen at the inducing centre was exchanged with nitrogen bearing a bulky substituent, the directing influence of this new group was examined. Solvent effects influencing the cis/trans ratio of aziridine formation are discussed.

New Versatile Fluorinated Chiral Building Blocks:  Synthesis and Reactivity of Optically Pure α-(Fluoroalkyl)-β-sulfinylenamines

1996 ◽  
Vol 61 (26) ◽  
pp. 9635-9635 ◽  
Author(s):  
Alberto Arnone ◽  
Pierfrancesco Bravo ◽  
Silvia Capelli ◽  
Giovanni Fronza ◽  
Stefano V. Meille ◽  
...  
Keyword(s):  
Building Blocks ◽  
Optically Pure

Synthesis of Methoxy Substituted Centrally Chiral Triynes as Precursors of Functionalised Nonracemic Helicene-Like Compounds

2007 ◽  
Vol 72 (11) ◽  
pp. 1499-1522 ◽  
Author(s):  
Zuzana Krausová ◽  
Petr Sehnal ◽  
Filip Teplý ◽  
Irena G. Stará ◽  
Ivo Starý ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Building Blocks ◽  
Alkoxy Group ◽  
Modular Synthesis ◽  
Optically Pure ◽  
Alkyne Coupling

A modular synthesis of a series of methoxy substituted optically pure aromatic triynes (-)-(S)-5-9 and (-)-(R)-10 is presented. It relies on key operations such as substitution of benzylic bromine with an alkoxy group and aryl-alkyne coupling reaction to combine appropriate methoxy substituted benzene/naphthalene building blocks and chiral alkynol synthons such as (-)-(2S)-but-3-yn-2-ol and (-)-(1R)-1-phenylprop-2-yn-1-ol. The triyne molecules comprise a diphenylacetylene, 1-(phenylethynyl)naphthalene or 1,1'-ethyne-1,2-diyldinaphthalene core unit. They are intended to serve as [2+2+2] cyclisation precursors of methoxy substituted nonracemic helicene-like compounds with a penta-, hexa- and heptacyclic helical scaffold.

ChemInform Abstract: New Versatile Fluorinated Chiral Building Blocks: Synthesis and Reactivity of Optically Pure α-(Fluoroalkyl)-β- sulfinylenamines.

ChemInform ◽  
2010 ◽  
Vol 27 (37) ◽  
pp. no-no
Author(s):  
A. ARNONE ◽  
P. BRAVO ◽  
S. CAPELLI ◽  
G. FRONZA ◽  
S. V. MEILLE ◽  
...  
Keyword(s):  
Building Blocks ◽  
Optically Pure

Synthesis of novel optically pure β-lactams

2005 ◽  
Vol 83 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Yan Yang ◽  
Fengyun Wang ◽  
Fernande D Rochon ◽  
Margaret M Kayser
Keyword(s):  
Crystal Structures ◽  
Building Blocks ◽  
Baker’S Yeast ◽  
Staudinger Reaction ◽  
Baker's Yeast ◽  
X Ray ◽  
Pure Compounds ◽  
Optically Pure ◽  
Aspartyl Proteases

Several new β-lactams were synthesized as racemates via a Staudinger reaction. The corresponding optically pure compounds were obtained in subsequent biotransformation steps either through baker's yeast reduction or lipase resolution. Their absolute configurations were established. The X-ray crystal structures of three new substituted β-lactams are reported here. These compounds represent key building blocks for a variety of medicinally important molecules, including inhibitors of aspartyl proteases and Taxol® analogues.Key words: optically pure β-lactams, lipase resolutions, baker's yeast reductions, Staudinger reaction.

scholarly journals Chasing "Zampanalogs": Advancing the Synthesis of the Zampanolide Macrocycle

2021 ◽  
Author(s):  
◽  
Sophie Geyrhofer
Keyword(s):  
Building Blocks ◽  
Model Systems ◽  
Reductive Methylation ◽  
Ring Closing Metathesis ◽  
Methyl Group ◽  
Multiple Substrates ◽  
Hydroxy Groups ◽  
Optically Pure ◽  
Late Stages ◽  
Nanomolar Range

<p>(-)-Zampanolide (1), a natural product isolated from a marine sponge, is a microtubule-stabilizing agent that exhibits activity in the nanomolar range against various cancer cells, including in P-gp pump overexpressing cells. This attribute makes (-)-zampanolide an interesting target for further investigation. In this work, a new method for a modular and convergent total synthesis of optically pure zampanolide was investigated, which would also allow the generation of “zampanalogs” following the same basic strategy. Their biological activity may then be assessed to allow the elucidation of structure-activity relationships of (-)-zampanolide and its analogs in tubulin binding.  The synthetic plan consisted of the modular combination of four major fragments, which would be connected in the late stages of the synthesis and could therefore be easily exchanged to allow the generation of analogs. The C15-C16 bond would be connected via an alkynylation reaction, and a subsequent reductive methylation would install the trisubstituted alkene. The connections at C1 and C3 could be achieved through a Bestmann ylid linchpin reaction, while the macrolactonization would be completed using a ring-closing metathesis to form the C8-C9 alkene. The side chain could be attached at C20 using one of the established aza-aldol methods.  The fragments necessary for the formation of the macrocycle were synthesized successfully. The purification strategy throughout the synthetic route was rationalized and provides an improvement with respect to yield and time compared to work previously done in this research group. Alongside these fragments, modified fragments that were originally intended to serve as model systems were synthesized, which could also be used as building blocks in the synthesis of “zampanalogs”.  Several methods for a stereoselective alkynylation at C15 were tested. These led to only meager successes, so an approach using a non-stereoselective alkynylation, followed by oxidation and a stereoselective CBS-reduction, was chosen. For the installation of the trisubstituted alkene a reductive methylation with vitride was tested, but this only led to the reduction of the alkyne without methylation. This product may be employed for the synthesis of C17-desmethyl analogs. The reductive methylation at C16-C17 was ultimately achieved using the Gilman reagent in a similar manner to the installation of the C5 methyl group in the C3-C8 fragment.  A linchpin strategy with the Bestmann ylid simultaneously formed the connectivity at C1 and C3. This process was successfully performed on multiple substrates arising from the model systems used in the alkynylation and reductive methylation reactions, yielding precursors to the ring-closing metathesis and potentially enabling the synthesis of various analogs.  The ring-closing metathesis proved to be difficult in analogs lacking the C17 methyl group and cis-tetrahydropyran ring, and due to this tendency further investigations are necessary. Once the macrocycle has been closed, a global deprotection and oxidation of hydroxy groups is necessary to allow for the installation of the sidechain.</p>

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