Preferred Label : E, Z;
IUPAC definition : The approved stereodescriptors of stereoisomeric alkenesR sup 1 /sup R sup 2 /sup
C CR sup 3 /sup R sup 4 /sup ( R sup 1 /sup R sup 2 /sup , R sup 3 /sup R
sup 4 /sup ); neither R sup 1 /sup nor R sup 2 /sup need be different from R sup
3 /sup or R sup 4 /sup ), cumulenesR sup 1 /sup R sup 2 /sup C( C C) sub i n /i
/sub CR sup 3 /sup R sup 4 /sup and related systems e.g. R sup 1 /sup R sup 2 /sup
C NOH , HON C{[CH sub 2 /sub ] sub i n /i /sub } sub 2 /sub C NOH . The group of
highest CIP priority attached to one of the terminal doubly bonded atoms of the alkene,
oxime, etc. or cumulene (i.e. R sup 1 /sup or R sup 2 /sup ) is compared with the
group of highest precedence attached to the other (i.e. R sup 3 /sup or R sup 4 /sup
). The stereoisomer is designated as i Z /i (zusammen together) if the groups
lie on the same side of a reference plane passing through the double bond and perpendicular
to the plane containing the bonds linking the groups to the double-bonded atoms; the
other stereoisomer is designated as i E /i (entgegen opposite). The descriptors
may be applied to structures with a fractional bond order between one and two; and
to double bonds involving elements other than carbon. They are not used to describe
ring substitution relationships.;
Origin ID : E01882;
See also
The approved stereodescriptors of stereoisomeric alkenesR sup 1 /sup R sup 2 /sup
C CR sup 3 /sup R sup 4 /sup ( R sup 1 /sup R sup 2 /sup , R sup 3 /sup R
sup 4 /sup ); neither R sup 1 /sup nor R sup 2 /sup need be different from R sup
3 /sup or R sup 4 /sup ), cumulenesR sup 1 /sup R sup 2 /sup C( C C) sub i n /i
/sub CR sup 3 /sup R sup 4 /sup and related systems e.g. R sup 1 /sup R sup 2 /sup
C NOH , HON C{[CH sub 2 /sub ] sub i n /i /sub } sub 2 /sub C NOH . The group of
highest CIP priority attached to one of the terminal doubly bonded atoms of the alkene,
oxime, etc. or cumulene (i.e. R sup 1 /sup or R sup 2 /sup ) is compared with the
group of highest precedence attached to the other (i.e. R sup 3 /sup or R sup 4 /sup
). The stereoisomer is designated as i Z /i (zusammen together) if the groups
lie on the same side of a reference plane passing through the double bond and perpendicular
to the plane containing the bonds linking the groups to the double-bonded atoms; the
other stereoisomer is designated as i E /i (entgegen opposite). The descriptors
may be applied to structures with a fractional bond order between one and two; and
to double bonds involving elements other than carbon. They are not used to describe
ring substitution relationships.
http://archives.uness.fr/sites/unf3s/media/paces/Grenoble_1112/peuchmaur_marine/peuchmaur_marine_p04/peuchmaur_marine_p04.pdf
http://archives.uness.fr/sites/unf3s/media/paces/Grenoble_1112/peuchmaur_marine/peuchmaur_marine_p04/index.htm
2012
false
true
false
true
PACES / bac 1
France
French
educational course
stereoisomerism
E, Z
cis-trans isomers
stereoisomers
chirality
enantiomer
diastereoisomers
R, S
absolute configuration
Fischer–Tollens projection
conformer
chair, boat, twist
Newman projection
chair–chair interconversion
meso-compound
audiovisual aids
chemistry, organic
isomerism
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