Addition of Allenylzinc Reagents, Prepared in Situ from Nonracemic Propargylic Mesylates, to Aldehydes. A New Synthesis of Highly Enantioenriched Homopropargylic Alcohols

1999 ◽  
Vol 64 (14) ◽  
pp. 5201-5204 ◽  
Author(s):  
James A. Marshall ◽  
Nicholas D. Adams
Keyword(s):  
New Synthesis ◽  
Homopropargylic Alcohols

scholarly journals Copper-catalyzed synthesis of allenylboronic acids. Access to sterically encumbered homopropargylic alcohols and amines by propargylboration

2018 ◽  
Vol 9 (13) ◽  
pp. 3305-3312 ◽  
Author(s):  
Jian Zhao ◽  
Sybrand J. T. Jonker ◽  
Denise N. Meyer ◽  
Göran Schulz ◽  
C. Duc Tran ◽  
...  
Keyword(s):  
Homopropargylic Alcohols

Synthesis and application of allenylboronic acids is presented. The successful synthetic applications are based on the possibility of the versatile transformations of the unprotected B(OH)2 group in situ under the propargylboration conditions.

A New Synthesis of 4,5,6,7-Tetrahydropyrazolo[1,5-c]pyrimidines by a Retro-Mannich Cascade Rearrangement

2014 ◽  
Vol 67 (3) ◽  
pp. 420 ◽  
Author(s):  
Raffaele Colombo ◽  
Kyu Ok Jeon ◽  
Donna M. Huryn ◽  
Matthew G. LaPorte ◽  
Peter Wipf
Keyword(s):  
Mannich Reaction ◽  
Medicinal Chemistry ◽  
Hydrolysis Product ◽  
Building Blocks ◽  
Biological Applications ◽  
Heterocyclic Chemistry ◽  
New Synthesis ◽  
Rearrangement Process

We discovered a new retro-Mannich reaction of in situ prepared pyrazolopyridines to give pyrazolopyrimidines that have hitherto been underrepresented in the heterocyclic chemistry literature. The isolation of a linear hydrolysis product supports a mechanistic hypothesis for this rearrangement process. In order to establish a broader access and explore potential biological applications for these medicinal chemistry building blocks, we investigated the scope of the reaction and generated small amine- as well as amide-based libraries through reductive aminations and amide couplings, respectively.

Evidence for the in situ Formation of Copper Acetylides During Pd/Cu Catalyzed Synthesis of Enynes: A New Synthesis of Allenynols.

ChemInform ◽  
2004 ◽  
Vol 35 (23) ◽  
Author(s):  
Philippe Bertus ◽  
Fabien Fecourt ◽  
Claude Bauder ◽  
Patrick Pale
Keyword(s):  
Copper Acetylides ◽  
New Synthesis ◽  
In Situ Formation

New synthesis of spirocycles by utilizing in situ forming hypervalent iodine species

2011 ◽  
Vol 9 (20) ◽  
pp. 6899 ◽  
Author(s):  
Toshifumi Dohi ◽  
Tomofumi Nakae ◽  
Yohei Ishikado ◽  
Daishi Kato ◽  
Yasuyuki Kita
Keyword(s):  
Hypervalent Iodine ◽  
Iodine Species ◽  
In Situ Forming ◽  
New Synthesis

Probing Molten Salt Flux Reactions Using Time-Resolved in Situ High-Temperature Powder X-ray Diffraction:  A New Synthesis Route to the Mixed-Valence NaTi2O4

2004 ◽  
Vol 16 (6) ◽  
pp. 1153-1159 ◽  
Author(s):  
Margret J. Geselbracht ◽  
Liam D. Noailles ◽  
Lien T. Ngo ◽  
Jessica H. Pikul ◽  
Richard I. Walton ◽  
...  
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
Mixed Valence ◽  
Salt Flux ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Synthesis Route ◽  
New Synthesis

ChemInform Abstract: New Synthesis of Spirocycles by Utilizing in situ Forming Hypervalent Iodine Species.

ChemInform ◽  
2012 ◽  
Vol 43 (12) ◽  
pp. no-no
Author(s):  
Toshifumi Dohi ◽  
Tomofumi Nakae ◽  
Yohei Ishikado ◽  
Daishi Kato ◽  
Yasuyuki Kita
Keyword(s):  
Hypervalent Iodine ◽  
Iodine Species ◽  
In Situ Forming ◽  
New Synthesis

A new synthesis of in situ cyclopropanones and the observation of a thermal cyclopropanone–dienol rearrangement

1993 ◽  
Vol 71 (11) ◽  
pp. 1910-1918 ◽  
Author(s):  
C. Black ◽  
P. Lario ◽  
A.P. Masters ◽  
T.S. Sorensen ◽  
F. Sun
Keyword(s):  
Low Temperature ◽  
Alkyl Substituent ◽  
Unsaturated Ketone ◽  
Silyl Enol Ethers ◽  
New Synthesis ◽  
Synthetic Procedure ◽  
Rearrangement Reaction ◽  
Unstable Molecules ◽  
High Yields

A new in situ low-temperature synthesis of cyclopropanones from α,α′-dibromo ketones is described. The synthetic procedure is particularly well suited to NMR tube-scale experiments, which then easily allows one to spectroscopically characterize low-temperature solutions of these unstable molecules. Nine systems were studied, seven of which give high yields of the cyclopropanones at −78 °C or, in one case, −93 °C. The major rearrangement pathway of these cyclopropanones leads to an α,β-unsaturated ketone. The mechanism of this reaction has been studied in some detail, including deuterium isotope studies, and the direct observation of enols, silyl enol ethers, and dimers. The rearrangement reaction is postulated to involve the intermediacy of an oxyallyl, the transfer of a hydrogen from the anti-alkyl substituent of this oxyallyl to the oxyallyl oxygen atom, which leads to an enol, and then finally tautomerization of the enol to the ketone. The thermal stability of the cyclopropanones is directly related to the ease of this rearrangement and, in two cases studied here, the rearrangement takes place rapidly even at −95 °C and the cyclopropanones could not be observed. There is a remarkably strong correlation between cyclopropanone structure and reactivity, with the main structural factor being the external angles of the cyclopropanone substituents.

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