The
chirality of a helical, propeller or screw-shaped molecular entity. A right-handed
helix is described as
P (or plus), a left-handed one as
M (or minus).
The application of this system to the description of conformations considers the
torsion angle between two specified (fiducial) groups that are attached to the atoms linked by
that bond. The sign of the smaller
torsion angle between the fiducial groups defines the
chirality sense of the
helix. Rules for the selection of fiducial groups according to
priority are given by R.S. Cahn, C.K. Ingold and V. Prelog,
Angew. Chem.
78, 413-447 (1966),
Angew. Chem. Internat. Ed. Eng.
5, 385-415, 511 (1966).
Source:
PAC, 1996, 68, 2193
(Basic terminology of stereochemistry (IUPAC Recommendations 1996))
on page 2209
