[Shadow]

Is bicyclo[1.1.0]butane optically active? I don't think so, but I am unsure. Central chirality doesn't exist in it, but axial maybe?

[OrgXemProf]

1. Make a model of bicyclo[1.1.0]butane. I suggest that you use flexible (and preferably inexpensive!) models that can be bent easily to accommodate formation of highly strained rings.

Be certain to construct your model of this molecule with a cis ring junction. Otherwise, be prepared to sweep up the pieces from the floor.

2. Make another model of bicyclo[1.1.0]butane that is the mirror image of the first molecular model that you constructed in response to #1, above.

3. Are the two models that you constructed mutually superimposable? If so, then bicyclo[1.1.0'butane is achiral. If not, then this molecule is chiral.

[Shadow]

I don't have any models available. Any other method?

[SinkingTako]

Well there are always online simulations, like this on Google:

http://pubchem.ncbi.nlm.nih.gov/compound/Bicyclo_1.1.0_butane

Go to 3D conformers, click on interact and you can move it around!

On the other hand, you can always consider: How many chiral centres? are there any planes of symmetry? How many are there?

General rule is that if there is an internal plane of symmetry somewhere in the molecule, some chirality of the molecule will be lost, even if it has chiral centres. (but it doesn't mean that a compound with an internal plane of symmetry is non-chiral)

Might be helpful to look up meso compounds as well.

So do you think that your compound is chiral?

[Dan]

General rule is that if there is an internal plane of symmetry somewhere in the molecule, some chirality of the molecule will be lost, even if it has chiral centres. (but it doesn't mean that a compound with an internal plane of symmetry is non-chiral)

An internal plane of symmetry is proof of achirality - but the absence of one is not proof of chirality.