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Current Organic Synthesis
ISSN: 1570-1794
Current Organic Synthesis
Volume 4, Number 3, August 2007
Contents
Oxazolidin-2-one Ring, a Popular Framework in
Synthetic Organic Chemistry Part 2 [1]. Applications and Modifications
Pp. 238-307
G. Zappia, G. Cancelliere, E. Gacs-Baitz, G. Delle Monache,
D. Misiti, L. Nevola and B. Botta
[Abstract]
Various Approaches for the Synthesis of Organic Carbamates
Pp. 308-320
Devdutt Chaturvedi, Nisha Mishra and Virendra Mishra
[Abstract]
Manganese(III) Acetate: A Versatile Reagent in Organic
Chemistry Pp. 321-350
Ayhan S. Demir and Mustafa Emrullahoglu
[Abstract]
Abstracts
[Back to top]
Oxazolidin-2-one Ring, a Popular Framework
in Synthetic Organic Chemistry Part 2 [1]. Applications and
Modifications
G. Zappia, G. Cancelliere, E. Gacs-Baitz, G. Delle Monache,
D. Misiti, L. Nevola and B. Botta
The present review is mainly focused upon the use of C-substituted
oxazolidin-2-ones as chiral auxiliaries in the stereocontrolled
C-C and C-X (X = hetero atom) bond formation.
The recent progress in the stereoselective alkylation, cycloaddition
and aldol reaction, as well as in the 1,4-coniugate addition,
in [2+2]-photocycloaddition, in Lewis acid promoted free-radical
copolymerization reactions are discussed. Emerging new applications
of the oxazolidin-2-one nucleus, such as building blocks in
the design and preparation of foldamers or as organocatalyst
in enantioselective epoxidation reactions, will be also discussed.
[Back to top]
Various Approaches for the Synthesis of Organic Carbamates
Devdutt Chaturvedi, Nisha Mishra and Virendra Mishra
Organic carbamates classically have been synthesized using
harmful reagents like phosgene, its derivatives and carbon
monoxide. Recently, carbon dioxide has been used as a cheap
and harmless reagent as an alternative to harmful reagents
for the synthesis of organic carbamates in gaseous, supercritical
and electrochemical forms. The present review will deal the
synthesis of organic carbamates from various starting materials
from beginning to recent ones.
[Back to top]
Manganese(III) Acetate: A Versatile Reagent in Organic
Chemistry
Ayhan S. Demir and Mustafa Emrullahoglu
Free radical reactions have become increasingly important,
as well as a very attractive tool, in organic synthesis within
the last two decades, due to their powerful, selective, specific,
and mild reaction abilities. Mn(OAc)3
mediated oxidative free radical reactions have been extensively
developed in the last twenty years. Numerous regio-, chemo-,
and stereoselective synthetic methods have been developed
in both inter- and intramolecular reactions, and have detailed
the progress of Mn(OAc)3
mediated oxidative free radical reactions since the end of
the 19th century. The new
literature about the new synthetic methods on Mn(OAc)3
mediated carbon–carbon bond formation and carbon-oxygen
bond formation reactions has not been extensively reviewed.
The present paper summarizes the recent developments in oxidative
free radical reactions mediated by Mn(OAc)3.
Mn(OAc)3 mediated reactions
of conjugated systems (e.g., alkenes, alkynes, 1,3-alkadienes,
l,3-alkadiynes, 1-alken-3-ynes) with β-dicarbonyl
compounds, Mn(OAc)3 mediated
alkylation, such as the oxidative addition of an aldehyde
or ketone to alkenes, Mn(OAc)3
mediated free-radical cyclization of alkenes with active methylene
compounds in the presence of oxygen to afford the cyclic peroxides;
lactone synthesis by the Mn(OAc)3
mediated oxidative addition of carboxylic acids to alkenes,
Mn(OAc)3 mediated cyclization
of α-(methylthio)acetamides,
enamides, and β-keto
carboxamides to afford cyclic products.
Mn(OAc)3 oxidative free-radical
cyclizations of allylic β-dicarbonyl
compounds, for example, the cyclization of allylic β-ketoesters
to afford the corresponding γ-lactone.
The reaction of alkenes with sodium azide in the presence
of acetic acid was investigated to afford 1.2-diazides. The
selective oxidation of enones led to α'-acetoxy-enones
by Mn(OAc)3 oxidation. In
general, Mn(OAc)3 oxidations
are characterized by higher α'-regioselectivity
and chemical yields, and milder reaction conditions, in turn
tolerating many sensitive functional groups. The use of Mn(OAc)3
in combination with other carboxylic acids or manganese(II)
carboxylates extends this methodology to the preparation of
a variety of α'-acyloxyenones
that are otherwise inaccessible in a one-step procedure.
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