The Paternò–Büchi reaction, named after
Emanuele Paternò
Emanuele Paternò, 9th Marquess of Sessa was an Italian chemist and is credited with the discovery of the Paternò–Büchi reaction.
Biography
He was born in Palermo in 1847 as the Marquess of Sessa, in a branch of the House of Paternò. He stu ...
and
George Büchi
George Hermann Büchi (August 1, 1921 – August 28, 1998) was a Swiss organic chemist and professor at the Massachusetts Institute of Technology. "Paternò's reaction", known since the early twentieth century, was renamed to the "Paternò–Büch ...
, who established its basic utility and form,
is a
photochemical reaction Organic photochemistry encompasses organic reactions that are induced by the action of light. The absorption of ultraviolet light by organic molecules often leads to reactions. In the earliest days, sunlight was employed, while in more modern times ...
, specifically a
2+2 photocycloaddition, which forms four-membered
oxetane
Oxetane, or 1,3-propylene oxide, is a heterocyclic organic compound with the molecular formula , having a four-membered ring with three carbon atoms and one oxygen atom.
The term "an oxetane" or "oxetanes" refer to any organic compound containing ...
rings from an excited
carbonyl
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containing a ...
and reacting with an
alkene
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond.
Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...
.
:
With substrates
benzaldehyde
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 odor. ...
and
2-methyl-2-butene
2-Methyl-2-butene, 2m2b, 2-methylbut-2-ene, also beta-isoamylene is an alkene hydrocarbon with the molecular formula C5H10.
Used as a free radical scavenger in trichloromethane (chloroform) and dichloromethane (methylene chloride).
John Snow, th ...
the reaction product is a mixture of
structural isomers
In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a compound is another compound whose molecule has the same number of atoms of each element, but with logically distinct bonds between them. The term meta ...
:
:
Another substrate set is benzaldehyde and
furan
Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as furans.
Furan is a colorless, flammable, highly ...
or heteroaromatic ketones and fluorinated alkenes.
The alternative strategy for the above reaction is called the
Transposed Paternò−Büchi reaction.
See also
*
Aza Paternò−Büchi reaction
Aza Paternò−Büchi reaction involves an ππ* excited state of alkene reacting with a ground state imine. This strategy was developed by the laboratory Sivaguru and co-workers to overcome the shortcomings involving direct excitation of imines. T ...
- the aza-equivalent of the Paternò–Büchi reaction
*
Enone–alkene cycloadditions
In organic chemistry, enone–alkene cycloadditions are a version of the +2cycloaddition This reaction involves an enone and alkene as substrates. Although the concerted photochemical +2cycloaddition is allowed, the reaction between enones and ...
- photochemical reaction of an enone with an alkene to give a cyclobutene ring unit
References
{{DEFAULTSORT:Paterno-Buchi Reaction
Photochemistry
Organic reactions
Name reactions
Oxygen heterocycle forming reactions
Coupling reactions