|
Mini-Reviews
in Organic Chemistry
ISSN: 1570-193X
Mini-Reviews
in Organic Chemistry
Volume 3, Number 2, May 2006
Contents
Bacterial Aromatic Sulfonates - a Bucherer
Reaction in Nature? Pp.93-97
H. Budzikiewicz
[Abstract]
Fluorine Containing Molecules for Peptidomimicry:
A Chemical Act to Modulate Enzymatic Activity Pp.
99-115
C.E. Oyiliagu, M. Novalen and L.P. Kotra
[Abstract]
Diaryl Ketones as Photoactivators Pp.117-135
J. Pérez-Prieto, R.E. Galian and M.A. Miranda
[Abstract]
Asymmetric Baylis-Hillman Reaction: Use of Novel
Chiral Aldehydes as Electrophiles, Chiral Base Catalysts and
Auxilliaries Pp. 137-153
Palakodety Radha Krishna and G.V.M. Sharma
[Abstract]
TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl)
an Important Reagent in Alcohol Oxidation and its Application
in Synthesis of Natural Products Pp. 155-165
Marcus Vinícius Nora De Souza
[Abstract]
Aminomethylated Pyrroles: Casting a Spotlight
Pp. 167-184
Gheorghe Roman
[Abstract]
Abstracts
[Back to top]
Bacterial Aromatic Sulfonates - a Bucherer
Reaction in Nature?
H. Budzikiewicz
Aromatic sulfonic acids have been found in Nature only rarely
as bacterial metabolites, mostly with the sulfonate group
located on an oxygenated benzene ring. This suggests a mechanism
of formation as it is discussed for the first step of a Bucherer
reaction.
[Back to top]
Fluorine Containing Molecules for Peptidomimicry:
A Chemical Act to Modulate Enzymatic Activity
C.E. Oyiliagu, M. Novalen and L.P. Kotra
Fluorine atom has been used extensively
to modulate the properties of various peptide-like compounds
to modulate enzyme activities such as proteases. Fluorinated
functionalities such as trifluoromethyl group, difluoromethyl
group, fluoromethyl moiety and recently -CHF-S- were investigated.
This article discusses important fluorine containing peptidomimetics,
synthetic strategies, and the modulation of enzymic activities.
[Back to top]
Diaryl Ketones as Photoactivators
J. Pérez-Prieto, R.E. Galian and M.A. Miranda
The lowest lying triplet excited states
of diaryl ketones are usually long lived and can be photochemically
generated with high quantum yields. Hence, compounds of this
type are efficient triplet photosensitizers. Three major mechanisms,
namely hydrogen abstraction, energy transfer and electron
transfer, can be involved in the photosensitized processes.
This paper reviews recent examples on the relevance of diaryl
ketones as triplet photosensitizers in synthesis. In addition,
a number of applications are also presented. In general, the
literature coverage has been limited to the publications that
appeared during the last five years.
[Back to top]
Asymmetric Baylis-Hillman Reaction: Use of Novel Chiral
Aldehydes as Electrophiles, Chiral Base Catalysts and Auxilliaries
Palakodety Radha Krishna and G.V.M. Sharma
The present review highlights our recent research findings
in the field of asymmetric Baylis-Hillman reaction. In particular,
it elaborates on the following efficient aids: 1) utilization
of sugar-derived acrylates as chiral auxiliary for diastereoselective
Baylis-Hillman reaction; 2) use of novel chiral electrophiles
such as sugar-derived aldehydes and chiral 2,3-epoxy aldehydes
for the diastereoselective Baylis-Hillman reaction to obtain
valuable chiral adducts; 3) a novel prolinol derivative promoted
enantioselective Baylis-Hillman reaction and 4) intramolecular
Baylis-Hillman reaction wherein both the aldehyde and acrylate
component are part structure of the same molecular framework
to afford high de’s. This review also covers
the related research work from other groups on asymmetric
Baylis-Hillman reaction.
[Back to top]
TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl) an Important
Reagent in Alcohol Oxidation and its Application in Synthesis
of Natural Products
Marcus Vinícius Nora De Souza
The oxidation of alcohols is a fundamental transformation
in organic synthesis and a large number of reagents have been
developed for this purpose. In spite of the different methodologies,
the modern organic synthesis still requires more efficient
oxidant reagents. In this context, TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl)
has emerged as the chosen reagent. The aim of this review
is to highlight the TEMPO oxidation as a very important procedure
in the synthesis of natural products accomplished between
2000 and 2004.
[Back to top]
Aminomethylated Pyrroles: Casting a Spotlight
Gheorghe Roman
The chemistry and applications of aminomethylated
pyrroles are extensively reported by the present review. An
overall account of the synthetic approaches to pyrrole Mannich
bases is offered, with an emphasis on topics such as regioselectivity
(α-aminomethylation
over β-aminomethylation,
C-Mannich reaction versus N-Mannich reaction),
mono- and bis-aminomethylation, influence of substituents
in the pyrrole ring, chemoselectivity, or the special mention
of N-tert-butoxycarbonyl-2-[(tert-butyldimethylsilyl)oxy]pyrrole
as a substrate. The scope and limitations of the aldehyde
component and amine reagents in the Mannich reaction of pyrroles
have been explored, the use of preformed aminomethylation
reagents and catalysts with the view to improve yields or
stereoselectivity has been surveyed, and the mechanism and
by-products arising from the aminomethylation of pyrroles
have been outlined. Pyrrole Mannich bases have been portrayed
as excellent H-, C-, N-, O-, S-, and P-alkylating
agents as a direct consequence of their ability to replace
the easily leaving dialkylamino group with other nucleophiles,
and the involvment in ring closure processes leading to porphyrins,
or other miscellaneous reactions have also been included in
the broad coverage of these compounds’ reactivity. A
particular attention has been paid to the contribution of
pyrrole Mannich bases to drug discovery and advances in medicinal
chemistry.
|
