Cryptochirality in stereochemistry is a special case of chirality where due to the electronic properties of the chiral molecule its specific rotation is non-measurable. The term was introduced by K. Mislow in 1977.
For example the alkane 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 1 and achiral Diisopropylzinc 2 to the chiral (R)-alcohol 4 with enantiomeric excess 94%:
For chiral induction to be possible C-H bonds in the alkane are believed to interact with the pi electrons of the aldehyde.
- More on diisopropylzinc autocatalysis see: homochirality
- ^ Chiral Discrimination of Cryptochiral Saturated Quaternary and Tertiary Hydrocarbons by Asymmetric Autocatalysis Kawasaki, T.; Tanaka, H.; Tsutsumi, T.; Kasahara, T.; Sato, I.; Soai, K. J. Am. Chem. Soc.; (Communication); 2006; 128(18); 6032-6033. Abstract
- ^ 2-(3,3-dimethylbut-1-ynyl)pyrimidine-5-carbaldehyde
- ^ Cryptochirality and dendrimers Struijk, MP Peerlings, HWI Meijer, EW Polymer Preprints 37(2), 497-498 (1996) Article
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cryptochirality — noun A form of chirality in which the properties of the pair of chiral compounds are indistinguishable … Wiktionary
Chirality (chemistry) — L form redirects here. For the bacterial strains, see L form bacteria. Two enantiomers of a generic amino acid … Wikipedia
cryptochiral — adjective That exhibits cryptochirality … Wiktionary