Cryptochirality in stereochemistry

Stereochemistry

Stereochemistry, a subdiscipline of chemistry, involves the study of the relative spatial arrangement of atoms within molecules. An important branch of stereochemistry is the study of chiral molecules....

 is a special case of chirality

Chirality (chemistry)

A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....

 where due to the electronic properties of the chiral molecule its specific rotation

Specific rotation

In stereochemistry, the specific rotation of a chemical compound [α] is defined as the observed angle of optical rotation α when plane-polarized light is passed through a sample with a path length of 1 decimeter and a sample concentration of 1 gram per 1 millilitre. It is the main property used to...

 is non-measurable. The term was introduced by K. Mislow in 1977.

For example the alkane

Alkane

Alkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...

 5-ethyl-5-propylundecane or (n-butyl)ethyl(n-hexyl)(n-propyl)methane found in certain species of Phaseolus vulgaris has two enantiomeric forms without any observable optical rotation

It is still possible to distinguish between the two enantiomers by asymmetric synthesis with the (S)-alkane 3 in an autocatalytic system of the achiral aldehyde

Aldehyde

An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....

 1 and achiral Diisopropylzinc

Diisopropylzinc

Diisopropylzinc is an organozinc compound with the chemical formulaZnC6H14....

 2 to the chiral (R)-alcohol

Alcohol

In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

 4 with enantiomeric excess

Enantiomeric excess

The enantiomeric excess of a substance is a measure of how pure it is. In this case, the impurity is the undesired enantiomer .-Definition:...

 94%:

For chiral induction to be possible C-H bonds in the alkane are believed to interact with the pi electrons of the aldehyde.

Cryptochirality also occurs in polymer

Polymer

A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

ic systems growing from chiral initiator

Initiator

An initiator can refer to:* A person that takes an initiative in making something happen.* Modulated neutron initiator, a neutron source used in some nuclear weapons...

s for example in dendrimer

Dendrimer

Dendrimers are repetitively branched molecules. The name comes from the Greek word "δένδρον" , which translates to "tree". Synonymous terms for dendrimer include arborols and cascade molecules. However, dendrimer is currently the internationally accepted term. A dendrimer is typically symmetric...

s with lobes of different size attached to a central core.