Stereo-Concept note

A small note on stereoisomerism.

Sun Sep 17, 2023

R & S Configuration

Configuration: S

in cyclo compounds

Even numbered rings with diagonally oppositely substituted do NOT show optical but DO SHOW geometrical isomerism.

All other case MAY show optical isomerism and WILL Show geometrical isomerism

2 and 3	both Cis and enantiomers of each other.
l and m	both cis and same compound (homomer) and MESO(inactive)
1 and 4	both trans and enantiomers of each other.
k and n	both trans and enantiomers of each other.
1 vs [2 or 3]	diastereomers and cis trans of each other.
k vs [l or m]	diastereomers and cis trans of each other.

Both p and q are chiral and p_q is a site for geometrical isomerism (stereocentre)
Both p’ and q’ are chiral and p_q is a site for geometrical isomerism (stereocentre)
Both e and f are NOT chiral and p_q is a NOT a site for geometrical isomerism
Both e’ and f’ are NOT chiral and p’_q’ is a NOT a site for geometrical isomerism
p and q are 2 stereocenters (serving both optical and geometrical) HOWEVER for ONLY Geometrical Isomerism It will serves as single stereocenter.(Still 2 stereo centers for optical)