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The reaction process begins with the deprotonation of 2-nitropropane at the α carbon to form a 
Although originally developed for benzyl compounds, the reaction also works for
organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clay ...
, the Hass–Bender oxidation (also called the Hass–Bender carbonyl synthesis) is an organic oxidation reaction that converts benzyl
In organic chemistry, benzyl is the substituent or molecular fragment possessing the structure . Benzyl features a benzene ring () attached to a methylene group () group.
Nomenclature
In IUPAC nomenclature, the prefix benzyl refers to a subst ...
halides into benzaldehydes
Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful.
It is a colorless liquid with a characteristic almond-like od ...
using the sodium salt of 2-nitropropane
2-Nitropropane (2-NP) is a solvent. It is a colorless liquid and is classified as a nitro compound.
Preparation
2-Nitropropane is produced by the high-temperature vapor-phase nitration of propane, usually with impurities of 1-nitropropane. 2-N ...
as the oxidant. This name reaction A name reaction is a chemical reaction named after its discoverers or developers. Among the tens of thousands of organic reactions that are known, hundreds of such reactions are well-known enough to be named after people. Well-known examples include ...
is named for Henry B. Hass and Myron L. Bender
Myron Lee Bender (1924–1988) was born in St. Louis, Missouri. He obtained his B.S. (1944) and his Ph.D. (1948) from Purdue University. The latter was under the direction of Henry B. Hass. After postdoctoral research under Paul D. Barlett (H ...
, who first reported it in 1949.
:
The reaction process begins with the deprotonation of 2-nitropropane at the α carbon to form a resonance
Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillat ...
-stabilized anion
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...
. This compound then initiates an SN2 reaction to displace the benzyl halide. Unlike in the nitroaldol reaction, where the deprotonated carbon of the nitroalkyl group is the nucleophilic
In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they a ...
atom, it is instead an oxygen of the nitro itself that attacks the benzylic carbon. The ''O''-benzyl structure then undergoes a pericyclic reaction
In organic chemistry, a pericyclic reaction is the type of organic reaction wherein the transition state of the molecule has a cyclic geometry, the reaction progresses in a concerted fashion, and the bond orbitals involved in the reaction overlap ...
to produce a benzaldehyde, with dimethyloxime
In organic chemistry, an oxime is a organic compound belonging to the imines, with the general formula , where R is an organic side-chain and R’ may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substitu ...
as a byproduct.
:
Although originally developed for benzyl compounds, the reaction also works for allyl
In organic chemistry, an allyl group is a substituent with the structural formula , where R is the rest of the molecule. It consists of a methylene bridge () attached to a vinyl group (). The name is derived from the scientific name for garlic, ...
halides, giving the respective α,β- enones and enals.
References
Name reactions Organic oxidation reactions {{organic-chem-stub