Stereoselectivity in the ortho ester Claisen rearrangements of the E and Z isomers of .gamma.-(1,3-dioxan-4-yl)allyl alcohols

1990 ◽  
Vol 55 (7) ◽  
pp. 2108-2113 ◽  
Author(s):  
Kinichi Tadano ◽  
Masaki Minami ◽  
Seiichiro Ogawa
Keyword(s):  
Ortho Ester ◽  
Claisen Rearrangements ◽  
E And Z Isomers ◽  
Allyl Alcohols

ChemInform Abstract: ORTHO ESTER CLAISEN REARRANGEMENTS USING TRIMETHYL METHOXYORTHOACETATE

1981 ◽  
Vol 12 (33) ◽  
Author(s):  
G. W. DAUB ◽  
D. H. TERAMURA ◽  
K. E. BRYANT ◽  
M. T. BURCH
Keyword(s):  
Ortho Ester ◽  
Claisen Rearrangements

Ortho ester Claisen rearrangements using trimethyl methoxyorthoacetate

1981 ◽  
Vol 46 (7) ◽  
pp. 1485-1486 ◽  
Author(s):  
G. William Daub ◽  
Douglas H. Teramura ◽  
Kevin E. Bryant ◽  
Mark T. Burch
Keyword(s):  
Ortho Ester ◽  
Claisen Rearrangements

Stereodivergent Alkyne Hydrofluorination Using a Simple Practical Reagent

2020 ◽  
Author(s):  
Rui Guo ◽  
Xiaotian Qi ◽  
Hengye Xiang ◽  
Paul Geaneoates ◽  
Ruihan Wang ◽  
...  
Keyword(s):  
Bond Formation ◽  
Biologically Active ◽  
Dft Studies ◽  
Thermodynamic Control ◽  
Important Goal ◽  
Peptide Bonds ◽  
Metal Free ◽  
Vinyl Cation ◽  
E And Z Isomers ◽  
Vinyl Fluorides

Vinyl fluorides play an important role in drug development as they serve as bioisosteres for peptide bonds and are found in a range of biologically active molecules. The discovery of safe, general and practical procedures to prepare vinyl fluorides remains an important goal and challenge for synthetic chemistry. Here we introduce an inexpensive and easily-handled reagent and report simple, scalable, and metal-free protocols for the regioselective and stereodivergent hydrofluorination of alkynes to access both the E and Z isomers of vinyl fluorides. These conditions were suitable for a diverse collection of alkynes, including several highly-functionalized pharmaceutical derivatives. Mechanistic and DFT studies support C–F bond formation through a vinyl cation intermediate, with the (E)- and (Z)-hydrofluorination products forming under kinetic and thermodynamic control, respectively.<br>

scholarly journals Paramagnetic solid-state NMR assignment and novel chemical conversion of the aldehyde group to dihydrogen ortho ester and hemiacetal moieties in copper(ii)- and cobalt(ii)-pyridinecarboxaldehyde complexes

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20216-20231
Author(s):  
Ayelén F. Crespi ◽  
Verónica M. Sánchez ◽  
Daniel Vega ◽  
Ana L. Pérez ◽  
Carlos D. Brondino ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Nmr Assignment ◽  
Cobalt Complexes ◽  
Chemical Conversion ◽  
Aldehyde Group ◽  
Ortho Ester ◽  
Complex Chemical ◽  
Chemical Functionalization

The complex chemical functionalization of the aldehyde group was elucidated in copper and cobalt complexes for 4- and 3-pyridinecarboxaldehyde ligands.

Claisen rearrangements-XII

Tetrahedron ◽  
1984 ◽  
Vol 40 (16) ◽  
pp. 3129-3132 ◽  
Author(s):  
R.D.H. Murray ◽  
Z.D. Jorge
Keyword(s):  
Claisen Rearrangements

Peptide Modifications: Versatile Tools in Peptide and Natural Product Syntheses

Synlett ◽  
2019 ◽  
Vol 30 (11) ◽  
pp. 1289-1302 ◽  
Author(s):  
Phil Servatius ◽  
Lukas Junk ◽  
Uli Kazmaier
Keyword(s):  
Amino Acids ◽  
Natural Product ◽  
Bond Activation ◽  
Bond Formation ◽  
Side Chain ◽  
Peptide Backbone ◽  
Claisen Rearrangements ◽  
The Past ◽  
Allylic Alkylations ◽  
Peptide Modifications

Peptide modifications via C–C bond formation have emerged as valuable tools for the preparation and alteration of non-proteinogenic amino acids and the corresponding peptides. Modification of glycine subunits in peptides allows for the incorporation of unusual side chains, often in a highly stereoselective manner, orchestrated by the chiral peptide backbone. Moreover, modifications of peptides are not limited to the peptidic backbone. Many side-chain modifications, not only by variation of existing functional groups, but also by C–H functionalization, have been developed over the past decade. This account highlights the synthetic contributions made by our group and others to the field of peptide modifications and their application in natural product syntheses.1 Introduction2 Peptide Backbone Modifications via Peptide Enolates2.1 Chelate Enolate Claisen Rearrangements2.2 Allylic Alkylations2.3 Miscellaneous Modifications3 Side-Chain Modifications3.1 C–H Activation3.1.1 Functionalization via Csp3–H Bond Activation3.2.2 Functionalization via Csp2–H Bond Activation3.2 On Peptide Tryptophan Syntheses4 Conclusion

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