How many stereoisomers are possible for each of the following structures? Draw them, and name each by the R-S and E-Z conventions
a) 4-methyl-2,5-heptadiene
b) 1,2,5-trichloro-3-hexene
2 answers
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You could use S.M.I.L.E.S.
(Simplified Molecular-Input Line-Entry System)
CC=C(C)C=CC
4-methyl-2,5-heptadiene has two points of E/Z isomerism--the double bond--and one point for R/S isomerism-the central carbon.
When both bonds have the same isomerism the central carbon is symmetric.
When the bonds have different isomerism, the central carbon is chiral.
That's four stereoisomers.
C\C=C/C(C)\C=C/C
Z,Z-4-methyl-2,5-heptadiene
C/C=C/C(C)\C=C\C
E,E-4-methyl-2,5-heptadiene
C\C=C/[C@@H](C)\C=C\C
R,Z,E-4-methyl-2,5-heptadiene
C\C=C\[C@@H](C)\C=C/C
S,E,Z-4-methyl-2,5-heptadiene
(Simplified Molecular-Input Line-Entry System)
CC=C(C)C=CC
4-methyl-2,5-heptadiene has two points of E/Z isomerism--the double bond--and one point for R/S isomerism-the central carbon.
When both bonds have the same isomerism the central carbon is symmetric.
When the bonds have different isomerism, the central carbon is chiral.
That's four stereoisomers.
C\C=C/C(C)\C=C/C
Z,Z-4-methyl-2,5-heptadiene
C/C=C/C(C)\C=C\C
E,E-4-methyl-2,5-heptadiene
C\C=C/[C@@H](C)\C=C\C
R,Z,E-4-methyl-2,5-heptadiene
C\C=C\[C@@H](C)\C=C/C
S,E,Z-4-methyl-2,5-heptadiene
0 answers