Housane or bicyclo .1.0entane is a saturated

cycloalkane In organic chemistry, the cycloalkanes (also called naphthenes, but distinct from naphthalene) are the monocyclic saturated hydrocarbons. In other words, a cycloalkane consists only of hydrogen and carbon atoms arranged in a structure containing ...

with the formula C₅H₈. It is a colorless volatile liquid at room temperature. It was named "housane" because of its shape. 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 ring. The small size of the ring creates substantial ring strain in the structure. Cyclopropane itself ...

fused to

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

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

synthetic organic chemistry Organic chemistry is a subdiscipline within chemistry involving the 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.Clayden, J ...

Preparation

The first synthesis of housane was reported by

Criegee Rudolf Criegee (* May 23, 1902 in Düsseldorf; † November 7, 1975 in Karlsruhe) was a German organic chemist. Early life Criegee's family was wealthy. His father worked as a court director. The family was national liberal, Prussian and Prot ...

in 1957, where housane was obtained from the

pyrolysis The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''py ...

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.LeRoy H. Scharpen and Victor W. Laurie (1965): "Structure of cyclopentadiene". ''The Journal of Chemical Physics'', volume 43, issue 8, pages 2765-2766. It is often ab ...

. 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 a cycloalkene. It is of interest in research but currently has no practical applications. It is a colorless easily condensed gas. A modern synthesis involves the 2-step dehydration of cyclobutanol. The compound was first prepared ...

.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 a non-optically active member of 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 "sup ...

formally has (1''R'',4''S'')

absolute stereochemistry Absolute configuration refers to the spatial arrangement of atoms within a chiral molecular entity (or group) and its resultant stereochemical description. Absolute configuration is typically relevant in organic molecules, where carbon is bonded ...

. 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 with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simila ...

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions 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 to

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

. 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 Bromocyclopentane is an alkyl halide with the chemical formula C5H9Br. It is a colorless to light yellow liquid at standard temperature and pressure. Bromocyclopentane is a building block used in the synthesis of filaminast. Bromocyclopent ...

. Housane also reacts with

lead tetraacetate Lead(IV) acetate or lead tetraacetate is an organometallic compound with chemical formula . It is a colorless solid that is soluble in nonpolar, organic solvents, indicating that it is not a salt. It is degraded by moisture and is typically store ...

, forming ''cis''-1,3-diacetoxycyclopentane among other products. : Housane is thermally quite stable, isomerizing to cyclopentene at 330 °C.

References

Cyclobutanes Hydrocarbons Cyclopropanes Bicycloalkanes {{hydrocarbon-stub