Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
10.1002/adsc.201900104
Advanced Synthesis & Catalysis
COMMUNICATION
DOI: 10.1002/adsc.201900104
A Simple, Mild and General Oxidation of Alcohols to Aldehydes
or Ketones by SO2F2/K2CO3 Using DMSO as Solvent and
Oxidant
Gao-Feng Zha,a,† Wan-Yin Fang, a,† Jing Leng,a and Hua-Li Qina*
a School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road,
Wuhan, 430070, P. R. China
† These authors contributed equally to this work.
Received: ((will be filled in by the editorial staff))
delete if not appropriate))
such as the chromium or manganese-based
Abstract. A practical, general and mild oxidation of
primary and secondary alcohols to carbonyl compounds species (e.g., CrO3, pyridinium chloro- and
proceeds in yields of up to 99% using SO2F2 as electrophile
dichromate, MnO2, KMnO4),[4] hypervalent
iodine reagents,[5] and activated sulfoxides,[6]
in DMSO as both the oxidant and the solvent at ambient
temperature. No moisture- and oxygen-free conditions are
required. Stoichiometric amount of inexpensive K2CO3,
which generates easy to separate by-products, is used as the
base. Thus, 5-gram scale runs proceeded in nearly
quantitative yields by a simple filtration as the work-up.
The use of a polar solvent such as DMSO, which usually
promotes competing Pummerer rearrangement, is also
noteworthy. This protocol is compatible with a variety of
common N-, O-, and S-functional groups on (hetero)arene,
alkene and alkyne substrates (68 examples). The protocol
was applied (99% yield) to a formal synthesis of the
important cholesterol-lowering drug Rosuvastatin.
particularly dimethyl sulfoxide (DMSO), have all
been successfully employed for non-catalytic
selective oxidation of alcohols. Among them, the
latter has been established as one of the most
powerful and useful oxidants for alcohol
oxidation without the use of environmentally-
harmful heavy metals. In the past several
decades, great efforts have been spent to develop
suitable electrophilic reagents as activators for
DMSO such as carbodiimides (Pfitzner–Moffatt
oxidation),[7] trifluoroacetic or acetic anhydrides
or oxalyl chloride (Swern Oxidation),[6g,8] SO3
(Parikh–Doering oxidation),[9] P2O5 or SO3,[10]
phosgene,[11] bis(trichloro-methyl)carbonate[12]
Py
Keywords: oxidation; alcohols; carbonyl compounds;
sulfuryl fluoride; sulfoxide
and cyanuric chloride,[13] among others.
Unfortunately, almost all of the above suffer from
common disadvantages:[14] (1) low temperatures
to prevent undesired Pummerer rearrangement as
well as generation H2C=S(+)-CH3 species, which
is highly reactive towards alcohols in a non-
productive fashion; (2) narrow range of
compatible non-polar solvents, typically CH2Cl2,
to minimize the formation of methylthioalkyl
ethers; (3) challenging handling of the highly
Aldehydes and ketones are key intermediates in
the synthesis of a large variety of versatile
pharmaceuticals, fine chemicals, vitamins,
fragrances, materials and other chemical
transformations.[1] Therefore, the development of
methods for selective oxidation of alcohols to
aldehydes or ketones while avoiding undesirable
over-oxidation to carboxylic acids, esters or other
by-products is of great importance in both
academic research and industrial chemical
moisture-sensitive,
irritating
and
toxic
electrophilic activators; (4) large excess of
organic base, typically Et3N, which produces
large amounts of organic waste and necessitates
tedious work-up and purification. A "perfect"
electrophilic activator capable of negating at least
most of these drawbacks for laboratorial and
industrial chemistry would be highly desirable.
Sulfuryl fluoride (SO2F2), a colorless, odorless,
inexpensive (about 1$/kg),[15a] and relatively inert gas
(stable up to 400 ºC when dry) has recently attracted
significant attention as an electrophile to react with
phenols under mild basic conditions.[15] Herein, we
production.[2] Although
a
large variety of
transition-metal-catalyzed approaches (using Pd,
Ru, Fe, Cu, Pt, Au, Ir, Rh, etc.) are available for
selective oxidation of alcohols to aldehydes or
ketones, the use of conventional non-catalytic
oxidation processes is still the most
predominating strategy for oxidation of alcohols
to aldehydes (ketones) in both laboratories and
industry.[3] Numerous non-catalytic oxidants,
1
This article is protected by copyright. All rights reserved.