Functionalization and elaboration of ring A taxoid building blocks

1997 ◽  
Vol 75 (11) ◽  
pp. 1542-1551 ◽  
Author(s):  
Michael W. Tjepkema ◽  
Timothy Wong ◽  
Peter D. Wilson ◽  
Alex G. Fallis
Keyword(s):  
Building Blocks ◽  
Diels Alder ◽  
Allylic Alcohols ◽  
Organolithium Reagents

The elaboration of the ring A aldehydes 1, 7, and 11 into more highly functionalized intermediates for taxoid synthesis is described. An improved route to the triene 4 and the adduct 28b is reported. Additional condensations of selected aldehydes (1,7) with the organolithium reagents derived from the substituted halodienes 8 and 14 afforded the allylic alcohols 10 and 15 with a diastereoselectivity of ~5:1. Further manipulation of these products by the installation of an α-keto-acetylenic dienophile provided a taxoid precursor with the C2, C9, C10, C13, and C20 oxygens installed in the case of 23 (from 7), and the less functionalized systems 27 and 27a (from 1). Keywords: taxoid, paclitaxel, Diels–Alder, cyclohexene, dienes.

scholarly journals Furoic Acid and Derivatives as Atypical Dienes in Diels-Alder Reactions

2021 ◽  
Author(s):  
Razvan Cioc ◽  
Tom Smak ◽  
Marc Crockatt ◽  
Jan Kees Van der Waal ◽  
Pieter C A Bruijnincx
Keyword(s):  
Green Chemistry ◽  
Cycloaddition Reaction ◽  
Building Blocks ◽  
Diels Alder ◽  
Furoic Acid

The furan Diels-Alder (DA) cycloaddition reaction has become an important tool in green chemistry, being central to the sustainable synthesis of many chemical building blocks. The restriction to electron-rich furans...

scholarly journals Synthesis of fluorinated δ-lactams via cycloisomerization of gem-difluoropropargyl amides

2010 ◽  
Vol 6 ◽  
Author(s):  
Satoru Arimitsu ◽  
Gerald B Hammond
Keyword(s):  
Building Blocks ◽  
Alder Reaction ◽  
Diels Alder ◽  
Tandem Reaction ◽  
Enyne Metathesis ◽  
Metathesis Reaction ◽  
Ring Closing Metathesis ◽  
Diels Alder Reaction

gem-Difluoro-1,7-enyne amides are suitable building blocks for the synthesis of difluorodihydropyridinones via a ring-closing metathesis reaction, and of 4,4-difluoro-3-oxoisoquinolines through a ring-closing metathesis–enyne metathesis tandem reaction. These products, in turn, undergo a Diels–Alder reaction to yield heterotricyclic systems in moderate to good yields.

scholarly journals An aza-Diels–Alder route to quinoline-based unnatural amino acids and polypeptide surrogates

RSC Advances ◽  
2021 ◽  
Vol 11 (23) ◽  
pp. 14132-14139
Author(s):  
M. J. Umerani ◽  
H. Yang ◽  
P. Pratakshya ◽  
J. S. Nowick ◽  
A. A. Gorodetsky
Keyword(s):  
Amino Acids ◽  
Unnatural Amino Acids ◽  
Building Blocks ◽  
Solid Support ◽  
Diels Alder

The synthesis of quinoline-based unnatural amino acids and the subsequent preparation of polypeptide surrogates from these building blocks on solid support.

scholarly journals Endo and Exo Diels–Alder Adducts: Temperature-Tunable Building Blocks for Selective Chemical Functionalization

2018 ◽  
Vol 140 (15) ◽  
pp. 5009-5013 ◽  
Author(s):  
Emre H. Discekici ◽  
Andre H. St. Amant ◽  
Shay N. Nguyen ◽  
In-Hwan Lee ◽  
Craig J. Hawker ◽  
...  
Keyword(s):  
Building Blocks ◽  
Diels Alder ◽  
Chemical Functionalization ◽  
Selective Chemical

scholarly journals Multicatalytic Enantioselective Borrowing Hydrogen δ-Lactonization Strategy from β-Keto Esters and Allylic Alcohols

Synthesis ◽  
2017 ◽  
Vol 50 (04) ◽  
pp. 785-792 ◽  
Author(s):  
Adrien Quintard ◽  
Mylène Roudier ◽  
Jean Rodriguez
Keyword(s):  
Michael Addition ◽  
Building Blocks ◽  
Allylic Alcohols ◽  
Keto Esters ◽  
Borrowing Hydrogen ◽  
Quaternary Stereocenters

By combining an iron-catalyzed borrowing hydrogen of allylic alcohols with an enantioselective organocatalyzed Michael addition of β-keto esters followed by a subsequent DBU-promoted lactonization different enantioenriched δ-lactones have been synthesized with good enantioselectivities. The valuable building blocks, featuring in some cases challenging quaternary stereocenters, have been obtained with >90% ee.

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