Housane or bicyclo .1.0entane is a saturated

cycloalkane In organic chemistry, the cycloalkanes (also called naphthenes, but distinct from naphthalene) are the ring (chemistry), monocyclic Saturated and unsaturated compounds, saturated hydrocarbons. In other words, a cycloalkane consists only of hydroge ...

with the formula C₅H₈. It is a colorless, volatile liquid at room temperature. It was named "housane" because of its shape, which resembles a simple drawing of a house. Structurally, the molecule consists of

cyclopropane Cyclopropane is the cycloalkane with the molecular formula (CH2)3, consisting of three methylene groups (CH2) linked to each other to form a triangular ring. The small size of the ring creates substantial ring strain in the structure. Cyclopropane ...

fused to

cyclobutane Cyclobutane is a cycloalkane and organic compound with the formula (CH2)4. Cyclobutane is a colourless gas and is commercially available as a liquefied gas. Derivatives of cyclobutane are called cyclobutanes. Cyclobutane itself is of no commerc ...

. The synthesis of molecules containing multiple strained rings, such as housane, is a traditional endeavor in synthetic organic chemistry.

Preparation

The first synthesis of housane was reported by Criegee in 1957, where housane was obtained from the

pyrolysis Pyrolysis is a process involving the Bond cleavage, separation of covalent bonds in organic matter by thermal decomposition within an Chemically inert, inert environment without oxygen. Etymology The word ''pyrolysis'' is coined from the Gree ...

of 2,3-diazabicyclo .2.1ept-2-ene. : Housane can be prepared in several steps starting with

cyclopentadiene Cyclopentadiene is an organic compound with the chemical formula, formula C5H6. It is often abbreviated CpH because the cyclopentadienyl anion is abbreviated Cp−. This colorless liquid has a strong and unpleasant odor. At room temperature, ...

. Other methods include photolysis of 2,3-diazabicyclo .2.1ept-2-ene, pyrolysis of ''N''-Phenyl-2-oxo-3-azabicyclo .2.1eptane, and addition of methylene to

cyclobutene Cyclobutene is an organic compound with the chemical formula . It is a cycloalkene. It is a colorless gas that easily condenses. It is of interest in research but currently has no practical applications. A modern synthesis involves the 2-step deh ...

.P. G. Gassman, K. T. Mansfield "Bicyclo .1.0entane" Org. Synth. 1969, volume 49, pp. 1.

Structure and properties

* The two rings are fused in a ''cis'' configuration—this

meso compound A meso compound or meso isomer is an optically inactive isomer in a set of stereoisomers, at least two of which are optically active. This means that despite containing two or more stereocenters, the molecule is not chiral. A meso compound is su ...

formally has (1''R'',4''S'') absolute stereochemistry. The small size of the two rings prevents the ''trans'' isomer from existing, so the stereochemistry is not usually mentioned when discussing this structure. Housane is easily attacked by

bromine Bromine is a chemical element; it has chemical symbol, symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between th ...

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

. In the presence of a platinum catalyst at room temperature, it is hydrogenated into

cyclopentane Cyclopentane (also called C pentane) is a highly flammable alicyclic compound, alicyclic hydrocarbon with chemical formula C5H10, C5H10 and CAS number 287-92-3, consisting of a ring of five carbon atoms each bonded with two hydrogen atoms above and ...

. Reaction with

hydrogen bromide Hydrogen bromide is the inorganic compound with the formula . It is a hydrogen halide consisting of hydrogen and bromine. A colorless gas, it dissolves in water, forming hydrobromic acid, which is saturated at 68.85% HBr by weight at room temper ...

at lower temperatures affords bromocyclopentane. Housane also reacts with lead tetraacetate, forming ''cis''-1,3-diacetoxycyclopentane among other products. : Housane is thermally quite stable, isomerizing to cyclopentene at 330 °C.

References

Cyclobutanes Hydrocarbons Cyclopropanes Bicycloalkanes {{Hydrocarbons

Preparation

Structure and properties

See also

References